About

Why it exists

Many calculator sites bury the answer under ads and pop-ups, or hide how the number was made. This site shows the result first, then the formula, the assumptions, and the sources, so you can check the math yourself.

What you will find

50 calculators in 9 categories. Each page explains what it does, how it is calculated, how to read the result, and where it falls short. What-if cards let you test a change with one tap.

Who runs it

calculew is built and maintained by a small team. Pages are reviewed by J. A. Lewis and T. M. Lewis. A page shows a "Reviewed by" line only after one of them has checked it against its sources. Until then it shows the date it was last updated. We do not claim a review we have not done.

Legal details are in the Terms of Use and Privacy Policy.

What we don't do

calculew does not sell financial products and does not refer you to any lender or service. If ads appear, they are labeled and are not recommendations.

How we keep it accurate

Formulas come from primary sources where one exists, such as the CDC, NIST, the CFPB, and published research. Every calculator has unit tests with worked examples. Read the methodology for details, and see the disclaimers for what these estimates are not.

Get in touch

Found a wrong number or a confusing page? Email hello@calculew.app or use the contact page.