Estimation Accuracy
Compare estimated versus actual task hours to measure accuracy.
About Estimation Accuracy
The ratio of actual to estimated hours reveals the overrun percentage, and scaling the per-task gap by the task count shows the total impact. Tracking estimate accuracy calibrates future planning, since most teams systemically under-estimate by a predictable factor.
Formula
Estimation Accuracy
Overrun % = (actual / estimated - 1) x 100
- tasks
- Number of similar items the pattern applies to
Worked example
With the default values below, Estimation Accuracy returns Overrun Percent of 40.00%. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Estimated hoursminimum 1
- 10
- Actual hoursminimum 0
- 14
- Tasks estimatedminimum 1
- 5
Results
- Overrun Percent
- 40.00%
- Accuracy
- 71.43%
- Total Overrun Hours
- 20.00
Step by step
- 1Values used
- 2Estimation Accuracy
- 3Overrun Percent= 40.00
- 4Accuracy= 71.43
- 5Total Overrun Hours= 20.00
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Estimation Accuracy calculated?
Overrun % = (actual / estimated - 1) x 100 The ratio of actual to estimated hours reveals the overrun percentage, and scaling the per-task gap by the task count shows the total impact.
Why does Estimation Accuracy matter?
Tracking estimate accuracy calibrates future planning, since most teams systemically under-estimate by a predictable factor.
What values do I need to enter?
This calculator takes 3 inputs: Estimated hours, Actual hours, Tasks estimated. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.