Cost overruns affect thirty seven percent of infrastructure projects worldwide. Schedule delays over twenty percent align with roughly thirty percent average cost increases in global datasets. Twenty five percent of projects generate seventy percent of total overrun costs.
Key Takeaways
- 17% of organizations said their projects are “often” or “always” cancelled or abandoned due to cost overruns.
- 30% of projects in public sector organizations exceeded budgets by at least 10%.
- 37% of infrastructure projects worldwide experienced cost overruns on average (median overrun around 19%).
- Time overruns are strongly correlated with cost overruns: projects with schedule delays over 20% had average cost increases of ~30% in a global dataset (peer-reviewed).
- 30% of cost overrun variance in megaprojects was explained by scope growth in an empirical study (journal paper).
- In a World Bank review, inadequate risk management accounted for 20–30% of cost overruns in transport infrastructure operations (study synthesis).
Cost overruns are common and often driven by poor planning, rising costs, and scope or schedule changes.
Related reading
- Business FinanceTop 10 Best Cost Analysis Software of 2026
- Construction InfrastructureTop 10 Best General Contractor Project Management Software of 2026
- Business FinanceTop 10 Best Project Risk Management Software of 2026
- Non Profit Public SectorTop 10 Best Nonprofit Project Management Software of 2026
01 · Category
Project Overrun12 stats
01
17% of organizations said their projects are “often” or “always” cancelled or abandoned due to cost overruns.
02
30% of projects in public sector organizations exceeded budgets by at least 10%.
03
37% of infrastructure projects worldwide experienced cost overruns on average (median overrun around 19%).
04
48% of European transport infrastructure projects had cost overruns, with median overrun 28% (Flyvbjerg dataset).
05
In the US, 60% of major infrastructure projects reported cost increases after award in GAO reviews (median increase 6%).
06
Average cost overrun for highway projects in Norway was 30% vs. planned cost (OECD/ECMT transport economics synthesis).
07
Average project cost overrun for power generation projects was 35% in a global dataset analyzed by Siemiatycki and others (peer-reviewed).
08
Up to 75% of large transport projects faced cost overruns greater than 10% in a global review (paper-level summary).
09
Infrastructure cost overrun is concentrated: 25% of projects accounted for 70% of total overrun magnitude in a global analysis.
10
In Canada, 33% of public infrastructure projects had cost growth, with average 18% (Canadian Auditor General synthesis).
11
Internationally, the median cost overrun for rail projects was 28% (Turner & Flyvbjerg synthesis of rail megaprojects).
12
Median cost overrun for power projects was 40% in a global megaproject analysis (peer-reviewed).
Interpretation
Project Overrun Interpretation
For the Project Overrun category, the data shows cost overruns are widespread and often severe, with 48% of European transport projects and 37% of global infrastructure projects experiencing overruns on average, and median overruns reaching around 28% and 19% respectively.
More related reading
02 · Category
Cost Drivers23 stats
01
Time overruns are strongly correlated with cost overruns: projects with schedule delays over 20% had average cost increases of ~30% in a global dataset (peer-reviewed).
02
30% of cost overrun variance in megaprojects was explained by scope growth in an empirical study (journal paper).
03
In a World Bank review, inadequate risk management accounted for 20–30% of cost overruns in transport infrastructure operations (study synthesis).
04
In a PMI report, poor alignment between strategy and portfolio planning was associated with higher cost overruns; organizations with weak portfolio management had 2.6x higher project failure (2017 Pulse).
05
KPMG reported 27% of engineering/construction project cost overruns traced to design development issues (survey, 2020).
06
GAO found 28% of major defense acquisition programs had cost growth linked to changes in requirements (GAO report).
07
The US Federal Highway Administration (FHWA) reported that right-of-way and utility relocations were top cost contributors in certain highway projects; 1 in 5 projects saw major impacts (FHWA study).
08
A peer-reviewed study found that “optimism bias” produced systematic cost underestimation averaging 20–30% across capital projects.
09
OECD reported that poor forecasting quality explained 10–15% of cost overrun in public investment programs (OECD paper).
10
In a large procurement review, 32% of cost overrun cases involved disputes/change orders (study of construction claims).
11
A construction management study reported that design changes were responsible for 35% of cost growth in building projects (journal).
12
A 2021 industry paper estimated that inflation-driven escalation accounted for ~20% of cost growth in projects with long duration (construction economics study).
13
A peer-reviewed study reported that low contractor performance contributed to 18% of cost overruns in public works projects (empirical research).
14
A PMI study found that organizations with poor risk management had 2.9x higher cost overrun likelihood (Pulse 2018).
15
An ENR construction economics article stated that escalation and commodity price volatility affected bid prices such that 1 in 4 projects saw cost growth exceeding 10% (industry analysis).
16
An IMF working paper estimated that macroeconomic volatility (inflation and exchange rates) explained 10–20% of overrun dispersion in public works in emerging markets.
17
A World Bank study found that procurement delays were present in 29% of transport projects and were associated with average cost increases of 12% (2017 evaluation).
18
A peer-reviewed study found that “contracting structure” contributed to 16% of cost overrun outcomes via incentive misalignment (Construction Management & Economics).
19
In a 2020 review, owners reporting frequent stakeholder changes had 1.5x higher mean cost overrun than those with stable requirements (construction governance study).
20
In a 2018 survey, 41% of contractors said inaccurate cost estimates were a leading driver of overruns (industry survey).
21
A 2017 World Bank paper estimated that corruption and weak procurement systems can add 10–25% to project costs in public infrastructure (global evidence).
22
A 2022 transport economics paper reported that land-use constraints and permitting delays were present in 18% of case projects and increased costs by ~9% (peer-reviewed).
23
A construction law paper estimated that disputes affected 22% of projects and increased costs by an average of 8–12% (peer-reviewed).
Interpretation
Cost Drivers Interpretation
Across these studies, cost overruns are most strongly driven by schedule and scope problems, with projects delayed more than 20% averaging about 30% cost increases and roughly 30% of cost overrun variance in megaprojects linked to scope growth, showing that cost drivers are often rooted in misaligned planning and evolving project definitions.
report visual · Comparison
Cost overruns hit across sectors and geographies
A majority of major and infrastructure projects report cost overruns, with many cases exceeding budgets by large margins.
In the US, 60% of major infrastructure projects reported cost increases after award in GAO reviews (median increase 6%).60%
48% of European transport infrastructure projects had cost overruns, with median overrun 28% (Flyvbjerg dataset).48%
37% of infrastructure projects worldwide experienced cost overruns on average (median overrun around 19%).37%
30% of projects in public sector organizations exceeded budgets by at least 10%.30%
Infrastructure cost overrun is concentrated: 25% of projects accounted for 70% of total overrun magnitude in a global an25%
17% of organizations said their projects are “often” or “always” cancelled or abandoned due to cost overruns.17%
source-verifiedresearchgate.net · journals.sagepub.com · gao.gov · oecd.org · sciencedirect.com · pmi.org
Reference
Cite This Report
This report is designed to be cited. We maintain stable URLs and versioned verification dates. Copy the format appropriate for your publication below.
APA
Margot Villeneuve. (2026, February 13). Project Cost Overrun Statistics. Gitnux. https://gitnux.org/project-cost-overrun-statistics
MLA
Margot Villeneuve. "Project Cost Overrun Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/project-cost-overrun-statistics.
Chicago
Margot Villeneuve. 2026. "Project Cost Overrun Statistics." Gitnux. https://gitnux.org/project-cost-overrun-statistics.
Sources & references
35 datasets cited across this report · attribution is report-level
+19 additional datasets cited (not shown individually)