8 free calculators, no login — type a number, see what it means.
Put your escape rate, change failure rate and test flakiness side by side.
Turn a coverage target into the amount of code still to be tested.
Check whether your tests actually catch deliberate bugs, not just run the code.
Find files changed again and again by many people, where bugs tend to gather.
How many units are right the first time, and how many are reworked or scrapped.
Check whether automating a manual test pays for itself.
Express a defect rate as DPMO and as a sigma level.
Core test management measures from case counts and defects.