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

> Source: https://netray.co/tools/erp-uat-defect-burn-down-calculator
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Model open defects, new defect arrival, fix rate and retest failures to see if UAT exits on schedule and what fix rate you need.

## Category

erp-migration

## Audience

- ERP project manager
- Test lead
- Program sponsor

## Tool

**Kind:** calculator

**Inputs:**

#### Open defects today

**Key:** open_defects

**Type:** number

**Default:** 140

**Min:** 0

**Step:** 1

**Unit:** defects

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

#### New defects found per day

**Key:** new_per_day

**Type:** number

**Default:** 10

**Min:** 0

**Step:** 1

**Unit:** per day

**Help:** Use the last five working days average.

#### Defects fixed per day

**Key:** fix_per_day

**Type:** number

**Default:** 16

**Min:** 0

**Step:** 1

**Unit:** per day

**Help:** Fixes delivered to the test environment per working day.

#### Retest pass rate

**Key:** retest_pass

**Type:** slider

**Default:** 85

**Min:** 10

**Max:** 100

**Step:** 1

**Unit:** %

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

#### Working days until UAT exit

**Key:** days_left

**Type:** number

**Default:** 20

**Min:** 1

**Step:** 1

**Unit:** days

#### Open defects allowed at exit

**Key:** exit_open

**Type:** number

**Default:** 10

**Min:** 0

**Step:** 1

**Unit:** defects

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

**Outputs:**

#### Effective defects closed per day

**Key:** closed_day

**Expr:** fix_per_day * retest_pass / 100

**Format:** decimal

**Description:** Fixes that actually survive retest.

#### Net burn-down per day

**Key:** net_day

**Expr:** closed_day - new_per_day

**Format:** decimal

**Description:** Positive means the backlog is shrinking.

#### Projected open defects at deadline

**Key:** projected

**Expr:** max(0, open_defects - net_day * days_left)

**Format:** integer

**Primary:** true

#### Working days to reach exit level

**Key:** days_to_exit

**Expr:** if(gt(net_day,0), max(0, open_defects - exit_open) / net_day, 999)

**Format:** decimal

**Primary:** true

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

#### Fix rate needed to exit on time

**Key:** required_fix

**Expr:** (max(0, open_defects - exit_open) / days_left + new_per_day) / (retest_pass / 100)

**Format:** decimal

**Description:** Fixes per working day.

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

**Key:** met

**Expr:** if(lte(projected, exit_open), 1, 0)

**Format:** integer

**Chart:**

#### Projected open defects vs daily fix rate

**Type:** line

**X:** fix_per_day

**From:** 4

**To:** 40

**Steps:** 37

**Series:**

- projected

**Disclaimer:** 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.

## Content

**Intro:** 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.

**Sections:**

#### How to use it

**Body:** 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.

**Bullets:**

- 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

**Body:** 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

**Body:** 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

**Body:** 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.

**Bullets:**

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

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

**Faq:**

#### What are typical UAT exit criteria?

**Answer:** 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?

**Answer:** 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?

**Answer:** 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?

**Answer:** 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.

## Search terms

uat defect burn down, erp uat exit criteria, defect closure rate calculator, erp testing defect forecast, uat defect trend, defect burn down chart erp, erp uat completion forecast, retest failure rate

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