I kept ending up on calculator sites that give you a number and nothing else. No formula, no assumptions, no way to check whether the answer applies to you. Some of them are quietly wrong. So Chalk Calculator shows its work. Every page has the formula, a worked example with real numbers, the assumptions it made, and the part I think matters most, what it cannot tell you. Two decisions shaped it. Privacy is architectural, not a policy. There's no server. It's a static export on a CDN, so there is no endpoint that could receive what you type. Salary, loan amounts, card balances they live in browser memory and nowhere else. Sharing a result copies plain text rather than a link, because a URL with your salary in it ends up in browser history and server logs. Happy to answer anything, and genuinely interested in which calculators are missing, or if any information is incorrect!

Chalk Calculator

Calculators that show their work. No signup, no tracking.

Calculators that show their work. No signup, no tracking.