Test Estimation Calculator

A test estimate that is a single number is a promise nobody can keep - the work itself is uncertain, so the honest deliverable is a range. This calculator does the arithmetic that turns three guesses per task into an expected total with a stated confidence band, then converts the hours into days for the team you actually have, overhead included. The headline is the 95% upper bound: commit against that and the deadline stops being a coin flip.

• Estimate at task level, not project level: variances add, so smaller, better-understood tasks produce a tighter total.
• Use the pessimistic column honestly - it means the worst realistic case, not a padded number to protect yourself.
• If the uncertainty percentage is above roughly 30%, the estimate is really a request for more information: decompose the widest task before committing to anything.

Three-point estimation (PERT) replaces the single number most test estimates die by with a range: for each chunk of test work you give an optimistic, a most likely and a pessimistic hours figure, and the tool weighs them 4:1 toward the most likely case to produce an expected value, a standard deviation, and the confidence bands around the total. Because variances add rather than standard deviations, splitting one vague task into concrete ones narrows the overall range instead of widening it - which is the practical argument for estimating at task level. The calculator also converts effort into duration: productive hours per tester per day after the standing overhead of meetings, triage and support, effort in person-days and team-days, a calendar completion date that skips weekends, and optional effort per test case as a sanity check against the suite size. Export the whole estimate as a CSV or a Markdown table and drop it into a test plan or sprint note. Nothing is uploaded - every calculation runs in the browser.