What it means
Individual project overruns get explained away easily, because there is always a reason and the reason is usually true. Aggregating outcomes across every completed project removes that comfort, since a portfolio that consistently overruns is not suffering bad luck but poor estimating.
That is the whole point of the measure. It matters to finance because capital allocation depends on trust in the numbers presented at approval.
A business with a 90% on-budget rate can plan its cash with confidence, while one running at 55% must hold a much larger contingency, and that contingency is capital sitting idle instead of funding something else. Boards therefore treat the rate as an indicator of planning quality rather than of project management heroics.
Defining "on budget" is where most of the argument happens. Some organisations demand actual cost at or below the approved figure, while others allow a tolerance band, typically 5% or 10%, on the basis that estimating to the last dollar is neither possible nor useful.
Whichever definition is chosen, it has to be fixed in advance and applied to every project, or the metric becomes an exercise in redefinition. The other rule that keeps the measure honest is what happens to approved changes.
If a project's budget is formally increased mid-flight and the project is then judged against the new figure, almost everything will appear on budget forever. Mature organisations report against the original approved baseline as well as the revised one, and the gap between the two is often the most revealing number in the pack.
The measure works best when paired with an indication of size. Twenty small overruns of $2,000 matter less than one overrun of $500,000, so most reporting packs show the rate alongside the total value of the overspend and the largest individual variance.
In practice
Real-world examples.
Example
A construction contractor reports an on-budget delivery rate of 62% for the year, with almost every overrun tied to groundworks. It responds by commissioning site surveys before pricing rather than after award, and the rate recovers to 81% the following year.
Example
A software function completes 24 internal projects and delivers 21 within budget, a rate of 87.5%. The chief financial officer treats this as evidence that the department's estimates can be relied on and reduces the standing contingency from 15% to 8%, releasing capital for other work.
Example
A marketing team tracks the measure across 40 campaigns and finds that the overruns cluster in projects with three or more external agencies. The insight leads to a single lead-agency model, and the on-budget rate climbs from 68% to 85% over two years.
Think of it
“On-budget rate shows how often you finish within planned costs-budget adherence success.
Formula
Calculation
On-Budget Delivery Rate = (Projects Delivered Within Budget / Total Projects Completed) x 100
An engineering group completed 36 projects during the year, of which 27 finished at or under their approved budget.
On-Budget Delivery Rate = (27 / 36) x 100 = 75%
The 9 projects that overran had a combined approved budget of $3,600,000 and a combined actual cost of $4,140,000.
Total overspend = $4,140,000 - $3,600,000 = $540,000
Overspend as a percentage of the overrunning budgets = ($540,000 / $3,600,000) x 100 = 15%
If the group applied a 5% tolerance band instead of a strict test, and 3 of those 9 projects finished within 5% of budget, the rate would be reported as (30 / 36) x 100 = 83.3%. The underlying performance is unchanged, which is why the definition must be stated alongside the number.Case study
Seen in the real world.
Pelham Industrial Systems is a fictional manufacturer created here to illustrate how this metric can be gamed and then fixed. Its project office proudly reported an on-budget delivery rate of 94%, which sat awkwardly beside a capital programme that had overspent by $2,300,000 over three years.
The explanation was procedural rather than dishonest. Projects were measured against the most recently approved budget, and budget increases were routinely approved by the sponsoring director without going back to the investment committee, so a project could be re-baselined twice and still count as on budget at completion.
Pelham changed the reporting to show performance against both the original approved baseline and the current one. Measured against the original baseline the rate fell to 58%, and the difference put the re-baselining habit on the board's agenda for the first time. In this illustrative case the metric did not change behaviour until it was measured against a figure nobody could quietly move.
Watch out
Common mistakes.
- Measuring against a revised budget without also showing the original. Re-baselining can produce a near-perfect rate while the portfolio overspends badly.
- Treating all projects as equal. A rate calculated by counting projects gives the same weight to a $20,000 job and a $2,000,000 one, so the value of the overspend must be reported too.
- Excluding cancelled projects from the denominator. Money spent on work that was abandoned is real, and hiding it flatters both the rate and the portfolio.
Questions
People also ask.
Should a tolerance band be allowed?
Many organisations allow 5% or 10% because estimates are not meant to be exact, but the band has to be set in advance and applied identically to every project.
How does this relate to earned value management?
Earned value tracks cost performance while a project is running, whereas this rate scores the finished result, so the two work together as an early warning and a scorecard.
Does a very high rate mean the business is well run?
Not necessarily, since budgets padded generously at approval will nearly always be met, which is why the rate should be read alongside estimate accuracy and the size of contingencies requested.
From the founder's library
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