About Calcool
Calcool is a free hub of online calculators built around one belief: a calculator should show its work. Anyone can throw inputs into a box and print a number. The harder — and more useful — job is to explain the formula behind that number, demonstrate it with a worked example, and point to the authority the method comes from. That's what every page here tries to do.
Our accuracy standards
Each calculator is built to a simple checklist before it goes live:
- A stated formula. The exact math the tool runs is written out on the page, not hidden in code.
- A worked example. Real numbers, step by step, so you can sanity-check the calculator against the explanation.
- A cited source. Where a method comes from an authority — the IRS, the Social Security Administration, the Department of Labor, the Consumer Financial Protection Bureau, accounting and finance bodies — we link to it.
- Honest limits. When a result is an estimate (taxes, blood alcohol, fees that change), we say so clearly rather than implying false precision.
Every tool runs entirely in your browser. We don't upload, store or sell anything you type — the math happens on your device.
How to suggest a calculator
If there's a calculation you'd like to see here, or you spot a number that looks wrong, please get in touch at [email protected]. Corrections are taken seriously — if a formula or rate is out of date, we'd rather hear about it and fix it.
A note on sources
Calcool cites real, named institutions for the methods behind its tools, and we don't invent experts or fabricate credentials. Where rates change over time — tax brackets, platform fees, contribution limits — the calculators are designed to let you enter the current figures, so the tool stays accurate even between our updates.