Results
Removal efficiency and cost
- Total defects
- --
- Found before release
- --
- Escaped
- --
- DRE
- --
- Total cost of defects
- --
- Cost share from escapes
Calculator Library / Software Quality
Defect Removal Efficiency Calculator
Calculate defect removal efficiency from defects found by stage, see what your defects cost, and test what finding escapes earlier would save.
Tool
Count defects by the stage where they were found
DRE = defects found before release / total defects
| Stage | Defects found | Cost per defect ($) | Escaped to production? | Cost |
|---|
What if defects were found earlier?
Costs are your own estimates of the average effort and impact of fixing a defect found at that stage. Data saves in this browser only and nothing is sent to a server.
Where defects were found
Defects by stage
Instructions
How to use this app
- List the stages where defects are found, in order, from earliest to production.
- Enter the number of defects found at each stage over a release or period.
- Estimate an average cost to fix a defect at each stage, including investigation, fix, retest, and impact.
- Mark the stage that represents defects that escaped to customers.
- Use the what-if to see what moving some escapes to an earlier stage would save, then check it against real releases.
What This Defect Removal Efficiency Calculator Helps You Decide
This calculator shows how well a team's reviews and tests filter out defects before customers meet them. You count defects by the stage where they were found, assign an average cost to each stage, and the tool calculates defect removal efficiency (DRE), the total cost of defects, and how much of that cost comes from defects that escaped.
Use it to compare releases, to make the case for earlier review and prevention, and to check a what-if: what would it save if some escapes were found earlier?
Core Formulas
| Measure | Formula | Meaning |
|---|---|---|
| DRE | Defects found before release / total defects | Share of defects removed before customers saw them. |
| Cost of defects | Sum over stages of defects × cost per defect | Total effort and impact of fixing defects. |
| Escape cost share | Cost of escaped defects / total cost | How much cost comes from late discovery. |
| What-if saving | Defects moved × (escape cost − new stage cost) | Saving if some escapes had been found earlier. |
Worked Example: One Release
The pre-loaded rows show 12, 38, 45, 30, and 15 defects found at design review, code review, unit tests, system tests, and production, with assumed costs of $50, $80, $120, $300, and $1,500. Total defects are 140, DRE is 125 / 140 = 89.3%, and the total cost is $40,540. The 15 escapes cost $22,500, which is 56% of the total even though they are 11% of the defects.
Moving 6 escaped defects to code review would raise DRE to 131 / 140 = 93.6% and save 6 × ($1,500 − $80) = $8,520. The what-if changes only the stage counts. Real improvements also change how many defects are introduced.
Limits and Good Practice
- Costs are estimates. Build them from your own data on effort, delay, and customer impact, and state your assumptions.
- Defects introduced vary between releases, so compare DRE over several releases, not one.
- Use consistent definitions of defect and severity, and record where each was found.
- Use the results to improve the process. Do not use defect counts to rank individuals.
Defect Removal Efficiency Calculator Frequently Asked Questions
How is DRE calculated?
Defect removal efficiency equals defects found before release divided by total defects, where total is defects found before release plus defects found after release, expressed as a percentage. For example, 125 defects found before release and 15 found in production gives a DRE of 125 / 140, or about 89.3%.
What is a good DRE?
It varies widely by organization, product, and how defects are counted, so compare with your own history over several releases rather than a single benchmark. The trend and the cost of escaped defects matter more than an absolute number.
Where do I get the cost per defect?
Estimate the average effort to investigate, fix, retest, and release a defect at each stage, plus any customer impact for defects found in production. Time tracking, incident records, and support data can help. State your assumptions, because the values are estimates.
Is my data stored anywhere?
No. The calculator saves entries in your own browser using local storage and does not send anything to a server. Use Clear all to remove them.