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General KnowledgeTop 10 Best Diesel Generator Sizing Software of 2026
Top 10 diesel generator sizing software ranked by inputs, load modeling, and reporting for engineers, using EasyPower and other tools.
How we ranked these tools
Vendors set the topic, but our editors set the inclusion criteria and the evaluation framework before research starts.
Search agents gather the source set and the review record, including transcriptions of video reviews and podcasts.
Framework: Features 40% · Ease 30% · Value 30%
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EasyPower is the best fit for engineers who need repeatable diesel generator sizing studies with exportable outputs for consistent design handoffs, whereas Himoinsa Sizing Software works better for teams focused on standby or prime set selection with internally reviewable results.
Editor’s top 3 picks
Three quick recommendations before you dive into the full comparison below — each one leads on a different dimension.
EasyPower
Step-by-step load pickup simulation ties generator electrical performance back to the modeled event sequence.
Best for: Fits when engineers need repeatable diesel generator sizing studies with exportable outputs.
Generac Industrial Power Design Pro
Editor pickGenerator recommendation output that couples sizing results with Generac set selection inputs and formatted worksheets.
Best for: Fits when teams must repeat diesel sizing plus Generac set selection with documented assumptions.
MTU Onsite Energy PowerCalc
Editor pickMTU configuration-aware sizing workflow ties generator outputs to MTU engine and setup assumptions rather than only load math.
Best for: Fits when MTU-aligned generator sizing needs repeatable concept-design outputs and duty-based assumptions.
Comparison Table
EasyPower
enterpriseElectrical power system design and analysis software with generator sizing and backup power study capabilities.
Step-by-step load pickup simulation ties generator electrical performance back to the modeled event sequence.
EasyPower is engineered for recurring generator studies where loads, motor starting, and operating profiles need repeatable configuration across multiple set options. The tool can simulate load pickup steps and evaluate voltage response during events that commonly drive generator oversizing decisions. Output artifacts include engineer-readable worksheets and report exports that align with typical submittal workflows.
A key tradeoff is that getting defensible results depends on providing correct load and duty assumptions, because the calculator can only propagate what is modeled. It fits situations where the same site equipment list is refined iteratively during design, then the generator selection is rerun to converge on final kVA and voltage performance.
- +Load and generator sizing outputs stay linked to modeled electrical assumptions
- +Motor starting behavior is included in the sizing workflow
- +Step load pickup analysis supports event-driven generator selection
- +Reports and single-line exports reduce manual rework
- –Correct inputs for load duty and starting conditions require domain diligence
- –Automation depends more on repeatable study setup than on full API integration
- –Complex sites can require multiple iterations to converge on final settings
- –Workflows for harmonic and fault studies are less central than sizing and transient response
Consulting electrical engineers
Generator sizing for hospital transfer systems
Reduced oversizing risk
Industrial controls teams
Sizing for sequenced equipment startup
Clear startup feasibility
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Facilities engineering
Repeat generator studies across sites
Faster proposal turnarounds
Reuses consistent study templates and input sets to generate comparable sizing reports.
Best for: Fits when engineers need repeatable diesel generator sizing studies with exportable outputs.
Generac Industrial Power Design Pro
enterpriseGenerator sizing and specification software for industrial backup power system design.
Generator recommendation output that couples sizing results with Generac set selection inputs and formatted worksheets.
Generac Industrial Power Design Pro is designed around generator sizing tasks that start from a load list and end at a generator set recommendation with documented assumptions. The workflow supports typical standby and prime design steps such as setting operational mode, applying power factor and motor starting loads from the entered load data, and selecting a matching kW and kVA basis. Output materials focus on engineer review rather than consumer-style estimates, with figures formatted for internal submittals and checklist verification.
A key tradeoff is that sizing quality is tied to how precisely the entered load list captures starting loads, duty context, and voltage and phase details. It fits best when an electrical engineer or sales engineer repeatedly sizes projects against a consistent internal standards set and wants fewer spreadsheet-to-quote conversions. It is less efficient for early-stage screening when the project team only has vague load ranges, because the inputs still need to be specific enough to drive set selection.
- +Generator recommendation output links calculation results to Generac equipment selection
- +Load list driven workflow matches common sizing handoff needs for design documentation
- +Worksheet-style results make assumptions easy to check during review cycles
- +Supports motor starting load inclusion based on entered electrical parameters
- –Requires detailed load and starting data to avoid weak sizing accuracy
- –Less suited to early screening when loads are still ranges and estimates
Generac sales engineering teams
Quote-ready generator sizing from load lists
Fewer manual spreadsheet handoffs
Electrical design engineers
Design documentation for generator selection
Faster internal review cycles
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Standby power project managers
Repeatable sizing across similar sites
More consistent sizing outcomes
Standardizes generator selection inputs so similar projects produce consistent sizing outputs.
Best for: Fits when teams must repeat diesel sizing plus Generac set selection with documented assumptions.
MTU Onsite Energy PowerCalc
enterpriseManufacturer-provided power generation sizing and configuration tool for onsite energy systems.
MTU configuration-aware sizing workflow ties generator outputs to MTU engine and setup assumptions rather than only load math.
PowerCalc is a sizing workflow for diesel generator sets where engine and alternator configuration inputs influence the resulting selection outputs. It helps engineers move from load lists and operating conditions into generator set sizing results used for preliminary selection packages. The tool’s strongest fit is when the project expects MTU-specific configuration constraints to be reflected early. A common output pattern is repeatable sizing for multiple operating scenarios so teams can compare candidates side by side.
A key tradeoff is that the tool centers on MTU Onsite Energy configuration assumptions, so it is less ideal for vendor-neutral sizing across arbitrary alternator and engine catalogs. It works well when a project team needs quick iteration during concept design or when preparing a generator set selection worksheet for early stakeholder review. In cases requiring deep fault analysis, harmonic spectrum modeling, or detailed step load transient simulation, PowerCalc is typically not the only calculation layer needed.
- +Engine-aligned sizing inputs support MTU configuration constraints early
- +Scenario iteration supports comparing multiple operating profiles quickly
- +Duty-focused workflow fits preliminary generator set selection processes
- +Structured inputs reduce manual calculation errors for load assumptions
- –Vendor-neutral sizing across non-MTU engine and alternator options is limited
- –Deep transient and network fault studies require separate analysis tools
- –Advanced electrical modeling depends on the completeness of entered load data
- –Exports are useful for review packets but may not meet custom worksheet standards
Generator selection engineers
Concept design sizing from load lists
Faster preliminary candidate selection
Emergency power project teams
Standby generator duty determination
Consistent standby sizing package
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Facilities engineering leads
Scenario comparison during procurement planning
Reduced rework later
Compares multiple operating profiles to narrow the generator set selection before detailed studies begin.
Best for: Fits when MTU-aligned generator sizing needs repeatable concept-design outputs and duty-based assumptions.
Himoinsa Sizing Software
vertical specialistGenerator set selection and sizing software for industrial and commercial power applications.
Duty-case generator selection workflow that keeps standby versus prime assumptions explicit across the calculation set.
Himoinsa Sizing Software is a diesel generator sizing tool from Himoinsa that focuses on producing generator set selection results from electrical load inputs. Its main workflow centers on translating kW and kVA demands into generator sizing outputs with configuration options for real-world operating constraints.
- +Duty-case oriented sizing flow for standby versus prime comparisons
- +Generator set selection outputs that reduce manual spreadsheet translation
- +Configuration inputs support practical operating constraints for site conditions
- +Handover-ready calculation structure for internal review cycles
- –Transient and harmonic modeling depth is limited compared with specialized analyzers
- –External integration and API automation are not clearly exposed for bulk workflows
- –Load step sequencing checks are not as detailed as enterprise power simulation tools
- –Complex modeling often requires tight input governance to avoid misleading results
Best for: Fits when teams need consistent diesel generator sizing outputs for standby or prime duty with repeatable internal review.
PRAMAC Power Design Tools
vertical specialistProduct selection and sizing resources for standby and prime power generator applications.
Generator set selection worksheet and single-line diagram export generated from PRAMAC configuration-driven sizing inputs.
PRAMAC Power Design Tools performs diesel generator sizing and set selection workflows that translate electrical load inputs into generator configuration outputs. It supports mapping generator operating modes to selection outputs, then applies duty-related assumptions to drive the selected kW and kVA sizing results.
- +Generator selection outputs tie directly to PRAMAC set configuration constraints.
- +Single-line diagram export supports faster engineering handoff.
- +Duty-related operating mode inputs flow into sizing results.
- +Worksheet-style documentation is ready for internal review cycles.
- –Limited visibility into underlying electrical transient and fault math steps.
- –Less suitable for custom alternator models outside PRAMAC component catalog.
Best for: Fits when teams need PRAMAC-aligned diesel generator set selection artifacts with engineering handoff outputs.
ETAP
enterprisePower system simulation software with generator sizing and load analysis modules.
Generator set selection is driven by ETAP’s electrical network model, keeping downstream studies aligned without rebuilding assumptions.
ETAP provides diesel generator sizing inside a wider ETAP electrical design workflow that includes system modeling, protection checks, and single-line study artifacts. Generator set selection supports rating and operating scenarios tied to modeled electrical loads, with outputs geared toward engineering review rather than standalone calculator results.
- +Generator sizing uses the same electrical network model as load flow studies
- +Exports generator set selection artifacts consistent with ETAP single-line documentation
- +Supports iterative sizing as protection and network assumptions change in one project
- +Integrates generator studies with short-circuit and protection workflows
- –Sizing accuracy depends on how well the overall network and load model is built
- –Heavier project setup than formula-only calculators for quick one-off estimates
Best for: Fits when diesel generator sizing must stay consistent with protection, fault studies, and single-line deliverables.
SKM Power Tools
enterpriseElectrical power system analysis software supporting generator sizing and dynamic stability studies.
Schematic-linked generator sizing that stays consistent with SKM project configuration for study-ready handoff.
SKM Power Tools provides diesel generator sizing from schematic-driven system data, which is a distinct workflow versus form-based calculators. Its generator selection output ties into electrical modeling in SKM’s ecosystem, including unit ratings and protection study handoff for coordinated design review.
- +Sizing uses model inputs from SKM electrical system data, reducing manual re-entry
- +Exports consistent generator set selection worksheets that match single-line configuration
- +Supports iteration loops that update generator ratings after circuit changes
- +Integrates with SKM study workflows for protection coordination review
- –Requires an SKM project workflow, so it is harder to use as a standalone calculator
- –Transient and load-sequence modeling depth depends on linked study modules
- –Automation and API access are not described as a primary sizing interface
- –Handoffs can require manual review when switching standby to prime assumptions
Best for: Fits when teams already model power systems in SKM and need generator sizing tied to protection studies.
Cummins Power Suite
vertical specialistGenerator set specification and project sizing software for standby and prime power applications.
Cummins-specific equipment configuration linkage that keeps sizing assumptions aligned with the targeted set build and its documentation outputs.
Cummins Power Suite is a generator sizing workflow built around Cummins engine and generator-set data, with calculations that align equipment selection to electrical loading expectations. The software supports workload interpretation for standby and prime use cases, including load step behavior and operating conditions used in set rating and selection worksheets.
- +Tight coupling to Cummins set configuration inputs reduces cross-checking gaps
- +Produces consistent selection reports suited for generator set selection worksheets
- +Handles standby and prime rating contexts with condition-based inputs
- +Exports electrical documentation artifacts to limit manual data entry
- –Best results depend on using Cummins catalog data for equipment sizing inputs
- –Load analysis depth is limited compared with tools focused on IEEE 446 studies
- –Transient and power quality modeling is less granular for harmonic-heavy designs
- –Requires careful input governance to avoid mismatched operating and ambient assumptions
Best for: Fits when teams standardize on Cummins generator hardware and need repeatable selection outputs with fewer spreadsheet transfers.
Electrical Power Systems Design (ETPS)
enterprisePower system analysis software with dedicated generator sizing and load modeling modules.
Generator sizing outputs are formatted as engineering artifacts that remain consistent across load assumption revisions.
Electrical Power Systems Design (ETPS) performs diesel generator sizing by combining load modeling inputs with generator set selection outputs that engineers can place into project worksheets and single-line documentation workflows. The software supports common standby and prime sizing approaches and can generate outputs tied to machine selection decisions like alternator capacity and protective setpoints.
- +Repeatable calculation runs for generator set sizing revisions
- +Outputs align to equipment selection decisions like alternator capacity
- +Works well for standardized worksheets used across similar projects
- +Supports both standby and prime rating workflows in one tool
- –Requires disciplined input setup to maintain consistent sizing results
- –Limited fit for teams needing API-led integration with external models
- –Transient and fault studies require separate workflows beyond sizing
- –UI navigation can feel calculation-centric rather than project-centric
Best for: Fits when engineering teams need repeatable diesel generator sizing worksheets tied to equipment selection decisions.
Digsilent PowerFactory
enterpriseIntegrated power system analysis platform with generator sizing and protection modules.
Model-driven generator performance checks that reuse the same network for stability and fault studies, then carry results into relay coordination.
Digsilent PowerFactory is an engineering-grade power-system modeling tool that can support diesel generator sizing through detailed electromechanical and network studies. It covers load flow, short-circuit, and stability workflows, so generator voltage regulation, fault contribution, and transient behavior can be evaluated with consistent grid models.
- +Uses one consistent network model across load flow, faults, and stability studies
- +Supports generator reactance modeling tied to voltage and fault calculations
- +Enables protective relay coordination using the same short-circuit results
- +Exports single-line diagram representations for review and handoff
- –Sizing outputs depend on detailed model build effort and parameter sourcing
- –Diesel generator fuel consumption curve and fuel sizing workflows are not native generator sizing centers
- –Transient voltage dip and frequency droop checks require careful study setup
- –Automation and API surfaces need governance discipline for repeatable model provisioning
Best for: Fits when projects need power-system studies that turn diesel generator sizing into network-wide electrical verification.
Conclusion
After evaluating 10 diesel generator sizing software, EasyPower stands out as our overall top pick — it scored highest across our combined criteria of features, ease of use, and value, which is why it sits at #1 in the rankings above.
Use the comparison table and detailed reviews above to validate the fit against your own requirements before committing to a tool.
How to Choose the Right Diesel Generator Sizing Software
Diesel generator sizing software maps load lists into generator set sizing studies with outputs that engineers can reuse in handoff documents. This buyer’s guide covers EasyPower, Generac Industrial Power Design Pro, MTU Onsite Energy PowerCalc, Himoinsa Sizing Software, PRAMAC Power Design Tools, ETAP, SKM Power Tools, Cummins Power Suite, Electrical Power Systems Design, and Digsilent PowerFactory.
Across these tools, the main differences show up in how study assumptions travel from load definition into generator electrical behavior, engine or vendor configuration constraints, and downstream deliverables like generator set selection worksheets and single-line diagram exports.
Diesel Generator Sizing Software for engineering studies, set selection, and electrical verification
Diesel generator sizing software takes structured load assumptions and computes generator set recommendations that stay consistent across design revisions, including motor starting behavior and step load pickup events when the workflow includes sequence-aware simulation. EasyPower ties load and generator sizing outputs to the modeled electrical event sequence and keeps step-by-step load pickup simulation linked back to the modeled event order.
Other tools bias toward vendor-linked or network-model workflows. Generac Industrial Power Design Pro couples sizing results to Generac set selection inputs and formatted worksheets, while Digsilent PowerFactory reuses one consistent network model for generator performance checks across load flow, faults, and stability studies, then carry results into relay coordination. Engineers also need to account for whether the tool supports repeatable workflow automation, since several options focus on study setup discipline rather than API-led bulk integration for large generator fleets.
Diesel generator sizing study features that affect electrical outcomes
Sizing quality depends on whether the workflow carries the same load assumptions into generator electrical behavior and into the deliverables engineers reuse during handoff. The tools in this guide diverge most on how they model step events, how they connect to equipment selection worksheets, and whether they keep study networks consistent across later verification steps.
Sequence-aware load pickup with linked generator sizing
EasyPower includes step-by-step load pickup simulation and keeps generator electrical sizing tied to the modeled event order. This keeps generator sizing results traceable to the same sequence engineers model in the load study.
Vendor-aligned generator set selection outputs with worksheet handoff
Generac Industrial Power Design Pro turns sizing results into Generac set selection inputs and formatted worksheets. PRAMAC Power Design Tools produces PRAMAC configuration-driven generator set selection artifacts plus a single-line diagram export.
Engine or vendor configuration aware concept design workflows
MTU Onsite Energy PowerCalc ties sizing assumptions to MTU engine and setup constraints so concept iterations map to duty-based profiles. Cummins Power Suite couples sizing assumptions to Cummins set configuration inputs to reduce cross-checking gaps during generator set selection.
Network model continuity for downstream electrical verification
ETAP drives generator set selection from ETAP’s electrical network model so downstream studies stay aligned with the same assumptions. Digsilent PowerFactory reuses one consistent network model for load flow, faults, and stability checks, then carries generator performance checks into relay coordination.
Export consistency for single-line and set selection artifacts
PRAMAC Power Design Tools exports single-line diagrams from configuration-driven sizing inputs to shorten the handoff gap. SKM Power Tools exports generator set selection worksheets consistent with SKM single-line configuration so protection study teams reuse the same project context.
Choosing Diesel Generator Sizing Software by workflow philosophy and output discipline
The selection decision should follow the path from load list to electrical behavior to the artifacts that protection, commissioning, and procurement teams will reuse. These tools split into two practical philosophies: sequence-focused sizing studies that preserve event traceability, and network-first or vendor-linked workflows that preserve model continuity across later verification and handoff documentation.
Start from the event level engineers must defend
If the engineering deliverable must defend step load pickup behavior as a modeled event sequence, choose EasyPower. EasyPower links load and generator sizing outputs to the modeled electrical event order and includes motor starting behavior in the sizing workflow.
Choose the output coupling requirement for generator set selection
If teams must produce generator recommendations that feed directly into a specific vendor’s equipment selection inputs, choose Generac Industrial Power Design Pro. If teams must produce PRAMAC-aligned set selection worksheets plus single-line diagram exports, choose PRAMAC Power Design Tools.
Pick vendor or engine constraint handling when concept design is constrained
If design iterations must respect MTU engine and setup constraints early, choose MTU Onsite Energy PowerCalc. If design iterations must standardize on Cummins generator hardware so sizing assumptions match targeted set build documentation outputs, choose Cummins Power Suite.
Select based on whether the same electrical network must drive multiple studies
If generator sizing must stay consistent with protection, fault studies, and single-line deliverables inside one platform, choose ETAP. If the project must reuse one consistent network model across load flow, faults, and stability studies and then carry generator performance into relay coordination, choose Digsilent PowerFactory.
Decide whether the workflow can be used standalone or depends on an existing modeling environment
If engineers need a standalone generator sizing workflow that reduces manual translation into selection worksheets, choose EasyPower or Electrical Power Systems Design. Electrical Power Systems Design emphasizes repeatable calculation runs for generator set sizing revisions but is not positioned for API-led integration into external models.
Who Diesel Generator Sizing Software fits best
Teams with recurring design revisions benefit from tools that keep the same assumptions connected to electrical outcomes and to the artifacts used for handoff. Teams focused on electrical verification benefit when sizing is anchored to the same network model used later for faults and coordination.
Engineering teams running sequence-sensitive standby or prime studies
EasyPower supports step-by-step load pickup simulation and keeps generator sizing outputs linked to the modeled event sequence, which fits projects where transient pickup behavior must remain traceable.
Design teams producing vendor-specific generator recommendation packages
Generac Industrial Power Design Pro couples sizing results to Generac set selection inputs and formatted worksheets, and PRAMAC Power Design Tools produces PRAMAC selection outputs plus single-line diagram exports.
Power system modeling groups that must keep sizing aligned with protection studies
ETAP drives generator set selection from the same electrical network used for load flow and protection-adjacent studies, and Digsilent PowerFactory reuses one consistent network model across load flow, faults, stability, and relay coordination.
Projects constrained by engine vendor configuration during concept design
MTU Onsite Energy PowerCalc ties sizing workflows to MTU configuration-aware assumptions, and Cummins Power Suite ties outputs to Cummins equipment configuration inputs.
Common Diesel Generator Sizing Software mistakes that cause rework
Rework usually starts when load and starting inputs are treated as generic values rather than as modeled conditions that must match the workflow’s assumptions. Rework also happens when engineers expect a standalone sizing output to match later verification studies without carrying the same network model or configuration constraints into the downstream steps.
Treating starting and load duty details as interchangeable estimates
EasyPower requires correct inputs for load duty and starting conditions to produce accurate sizing results because it links sizing outputs to the modeled electrical event sequence. Generac Industrial Power Design Pro also depends on detailed load and starting data to avoid weak sizing accuracy.
Picking a generator sizing tool without confirming it preserves handoff artifacts
PRAMAC Power Design Tools provides a single-line diagram export generated from configuration-driven sizing inputs, so teams that rely on single-line handoffs should validate this workflow early. ETAP and Digsilent PowerFactory keep downstream studies aligned because they start from the same electrical network model.
Expecting deep electrical transient and fault work from a generator sizing workflow alone
Himoinsa Sizing Software limits transient and harmonic modeling depth compared with specialized analyzers, so teams needing those studies should plan separate transient and fault analysis tools. EasyPower focuses on sequence-aware load pickup simulation and links electrical event order to sizing outcomes rather than replacing full network fault analysis.
Using a vendor configuration tool for vendor-neutral equipment selection
MTU Onsite Energy PowerCalc limits vendor-neutral sizing across non-MTU engine and alternator options, so teams with mixed equipment catalogs should consider ETAP or Digsilent PowerFactory. Cummins Power Suite works best when Cummins catalog data drives equipment sizing inputs.
How We Selected and Ranked These Tools
We evaluated EasyPower, Generac Industrial Power Design Pro, MTU Onsite Energy PowerCalc, Himoinsa Sizing Software, PRAMAC Power Design Tools, ETAP, SKM Power Tools, Cummins Power Suite, Electrical Power Systems Design, and Digsilent PowerFactory using feature depth, workflow fit, and study output discipline. Features account for 40% of the ranking because tools like EasyPower differentiate through step-by-step load pickup simulation that stays linked to the modeled electrical event sequence.
Ease and value each account for 30% because teams must iterate sizing inputs repeatedly without losing traceability into generator set selection worksheets and single-line deliverables. EasyPower ranked first because its standout ties modeled electrical events to generator electrical performance outputs and includes motor starting behavior within the sizing workflow.
Frequently Asked Questions About Diesel Generator Sizing Software
How does EasyPower model step load pickup compared with ETAP’s generator sizing inside a system study?
Which tool couples generator sizing with vendor equipment selection inputs rather than treating sizing as a standalone calculator?
How does MTU Onsite Energy PowerCalc handle duty class assumptions for standby versus continuous use cases?
What breaks if generator sizing is updated after load changes but protective studies are not linked to the sizing project model?
When do SKM Power Tools’ schematic-driven sizing workflows matter for handoff to protection studies?
Which tool produces single-line diagram export artifacts directly from generator selection inputs?
How does Digsilent PowerFactory turn generator sizing into network-wide verification beyond steady-state equations?
How should teams plan data migration when moving between sizing tools that use different input structures and export formats?
What security and access-control expectations differ between tools that operate as standalone sizing calculators and those embedded in multi-user electrical design projects?
Tools reviewed
Primary sources checked during evaluation.
Referenced in the comparison table and product reviews above.
Funding and competing interests
This study was co-funded by several of the vendors assessed in it. No single vendor funded it. Funders could propose the market studied.
They had no role in selecting vendors, setting or weighting criteria, analysing data or drawing conclusions, and they received the same factual-accuracy check as every other vendor assessed.
Market definition, inclusion rules and criteria weights were fixed by an editor before research began and did not change afterwards. Editorial process →
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