The Formula Check Worksheet
A formula that looks convincing still needs a test with an answer you calculated independently.
- The complete prompt
- A practical checklist and example
- A PDF to save or print
Copy the prompt
The Formula Check Worksheet
Explain this Excel formula in plain language. Identify every input cell, percentage assumption, rounding rule and error fallback. Propose test cases, including normal inputs, blank inputs, invalid text and boundary values. Do not mark it verified until I supply Excel's actual results. Formula: [paste].
A formula that looks convincing still needs a test with an answer you calculated independently.
Your next check
Compare my independent expected values with the observed Excel results below. Identify mismatches and possible reference or assumption errors. Keep untested cases marked untested.
Test log: A2 quantity 3 | B2 price 20 | C2 discount 10% | expected 54 | actual [ ]. Next: quantity 0 expects 0; discount 0% expects 60; discount 100% expects 0. Check whether those inputs are allowed for your task.
How to use it
Write the meaning first
State what each cell means and whether a discount is entered as 10% or 10. These are different inputs.
Calculate independently
For quantity 3, unit price 20 and discount 10%, the expected total is 54. Calculate this separately from the formula.
Run and record
Test =IFERROR(ROUND(A2*B2*(1-C2),2),"CHECK INPUT"). Record inputs, expected result, actual Excel result and pass/fail for each case.
Test beyond one row
Try 0 quantity, 0% discount, 100% discount and invalid text. Inspect references when copying rows. IFERROR catches formula errors; it does not prove the business logic is correct.
Official references checked Sep 10, 2026. Features and limits can change.
- Microsoft: IFERROR
Official reference
- Microsoft: rounding
Official reference
Use this guide on its own, then explore more free prompts when you need them.
Explore more resourcesReal builds, no jargon, no gatekeeping. One issue a week.
Anyone can learn this. The gate is intimidation.
@keybuilds.ai →