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ERP UAT Defect Burn-Down Calculator: Will You Hit Exit Criteria in Time?

Every UAT status meeting asks one question: will we be at exit criteria by the end date? This calculator answers with simple arithmetic on open defects, discovery rate, fix rate and retest failures, and tells you the fix rate required if you are behind.

Your numbers

Open defects today

defects

Open count at the agreed severity level, for example severity 1 to 3.

New defects found per day

per day

Use the last five working days average.

Defects fixed per day

per day

Fixes delivered to the test environment per working day.

Retest pass rate

85 %

Share of fixes that pass retest first time; the rest are reopened.

Working days until UAT exit

days

Open defects allowed at exit

defects

From your exit criteria, usually zero for the highest severities.

Your results

Projected open defects at deadline

Working days to reach exit level

36.1111

A value of 999 means the backlog is not shrinking at the current rates.

Effective defects closed per day

13.6

Fixes that actually survive retest.

Net burn-down per day

3.6

Positive means the backlog is shrinking.

Fix rate needed to exit on time

19.4118

Fixes per working day.

Exit met by deadline (1 = yes, 0 = no)

Linear forecast. New defects usually decline late in UAT, so the result is conservative when discovery is slowing and optimistic when new test areas open.

Save results:

Projected open defects vs daily fix rate

Sweeps Defects fixed per day from 4 to 40, holding your other inputs fixed.

Want a live defect forecast?

We can connect your test and ERP data to a self-updating burn-down view.

Optional. The tool and every export work without this. No spam.

How to use it

Enter the open count at the severity levels your exit criteria cover, then average the last five working days for new defects found and defects fixed. Add the retest pass rate from your test tool, found by dividing fixes that closed by fixes delivered. Set the remaining days and the number of defects allowed at exit. The calculator shows the net daily burn-down, the projected open count at the deadline and whether exit is met.

Use the same severity filter for every input
Average at least five working days
Count reopened defects as failed retests
Update the figures at each daily stand-up

The formula

Effective closures per day = fixes per day x retest pass rate. Net burn = effective closures - new defects per day. Projected open = max(0, open - net burn x days left). Days to exit = (open - allowed) / net burn when burn is positive. Required fix rate = ((open - allowed) / days left + new per day) / pass rate. The chart sweeps the fix rate to show how much extra development capacity changes the result.

Reading the result

If net burn is zero or negative, the team is fixing as fast as it finds problems and the date is at risk regardless of effort; look at root causes, such as unclear requirements or an unstable configuration. If the required fix rate is far above the current rate, choose between a date move, a scope cut in UAT, or adding developers, and price the date move with a delay cost estimate.

Common mistakes

Mixing severity levels hides the real picture, since a pile of cosmetic issues is not a go-live blocker. Another mistake is ignoring retest failures, which can turn a healthy-looking fix rate into a flat backlog. Finally, do not treat a one-day spike as the trend; use an average.

Mixing severities in one count
Ignoring reopened defects
Using a single-day rate
Not re-baselining after scope changes

Frequently Asked Questions

What are typical UAT exit criteria?

Common criteria are zero open severity 1 defects, no more than a small agreed number of severity 2 with workarounds, and a minimum pass rate on critical business scenarios. Set yours in the test plan and have the steering committee sign off.

Why does the retest pass rate matter?

A fix that fails retest returns to the backlog, so only passing fixes reduce open defects. A fix rate of 20 per day with a 70 percent pass rate closes only 14 per day, which can be lower than the discovery rate.

What does 999 days to exit mean?

It means the net burn-down is zero or negative, so open defects will not fall to the exit level at current rates. Raise the fix rate, lower the discovery rate by improving build quality, or change the date.

Is the linear forecast reliable?

It is a quick planning guide. Real curves flatten as test coverage completes. Use it for direction and the required fix rate, and cross-check against test execution progress, which shows how many scenarios are still untested.

If you want defect, test and fix data from your ALM and ERP environments consolidated into one live forecast, Netray can build it.

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