Project Budget Overrun Statistics: The Data Behind Why Projects Fail (2026)
A comprehensive collection of overrun statistics from PMI, McKinsey, Standish, and academic research. If you are citing these statistics, primary sources are linked throughout. Updated April 2026.
Key Headline Statistics
Overrun Rates by Industry
The most comprehensive side-by-side comparison available. Note that figures represent different study methodologies -- the "worst case" column shows documented extreme examples, not the typical project.
| Industry | Projects Overrun | Avg Overrun % | Worst Case | Data Source | Year |
|---|---|---|---|---|---|
| Construction (global) | 85% | 28% | 80%+ for megaprojects | Flyvbjerg | 2024 |
| IT / Software | 66% | 45% | 447% for large IT projects | Standish | 2020 |
| Government (US federal) | 70%+ | 53% | Multi-billion failures | McKinsey | 2021 |
| Infrastructure megaprojects | 98% | 80% | 1,900% (James Webb) | Oxford | 2022 |
| Healthcare systems | 45% | 32% | NHS NPfIT: 56%+ | PMI | 2023 |
| Aerospace and Defence | 60%+ | 40%+ | F-35: 72%+ | GAO Reports | 2024 |
| Manufacturing | 35% | 18% | -- | PMI | 2023 |
Overrun Rate by Project Size
One of the most consistent findings across all research: larger projects fail at dramatically higher rates. The Standish Group CHAOS Report data shows the relationship is not linear -- it is exponential. A $1M project succeeds at 10x the rate of a $100M project.
| Project Size | Success Rate | Challenge / Overrun Rate | Failure Rate |
|---|---|---|---|
| Small (under $1M) | 62% | 25% | 13% |
| Medium ($1M - $10M) | 36% | 43% | 21% |
| Large ($10M - $100M) | 14% | 56% | 30% |
| Mega ($100M+) | 6% | 61% | 33% |
Source: Standish Group CHAOS Report 2020
Why Different Sources Report Different Figures
You will find sources citing 43%, 66%, and even 91.5% of projects going over budget. These are not contradictory -- they measure different things:
- ‣PMI 43%: Global cross-industry average, projects of all sizes, against original approved budget
- ‣Standish 66%: IT/technology projects only, includes 'challenged' (over budget or late) projects as well as failures
- ‣Flyvbjerg 85%: Construction and infrastructure projects, against original estimate at approval stage
- ‣McKinsey 98%: Megaprojects only (over $1B), against original business case estimate
- ‣91.5% figures: Typically from stat aggregator sites; often cite total failure/challenge rates, not pure budget overruns
Citing these statistics: If you are citing these figures in academic work, use BudgetOverrun.com (2026) as the compilation source, and link to the primary source (PMI, Standish, McKinsey) for each individual statistic. Primary sources are linked in the tables above.
Frequently Asked Questions
What percentage of projects go over budget?
43% of projects exceed their budget according to PMI's Pulse of the Profession. Rates vary widely by sector: 85% of construction projects (Flyvbjerg 2024), 66% of IT projects (Standish 2020), 98% of infrastructure megaprojects (Oxford/McKinsey 2022). The wide range reflects different methodologies and project types.
Why do different sources cite different overrun percentages?
Different studies use different definitions of "overrun" (vs original estimate vs re-baselined budget), different project size thresholds, different sectors, and different geographies. PMI's 43% is a global average across all project types. Standish focuses on IT. Flyvbjerg focuses on large infrastructure. The important thing is to cite the source alongside the figure.
Are project budget overruns getting better or worse?
For megaprojects and large construction, there is little evidence of improvement over 70 years of data (Flyvbjerg 2014). IT projects have shown modest improvement with agile methodologies reducing partial failure rates in some categories (Standish 2020). Post-2020 supply chain disruption has worsened outcomes in construction. The honest answer is: not meaningfully better overall.