Who is behind KeypadLab
I'm Maximilian Wulf, a photographer based in Mainz, Germany. My day-to-day work involves plans, measurements and numbers. I constantly need small calculations: a roof pitch from degrees to percent, the number of steps in a staircase, a discount or a rule of three. Most online calculators for this are cluttered, full of ads or give answers without explanation. KeypadLab is my alternative.
How the tools are made
- Show the formula. Every tool shows how it calculates and explains the formula underneath in plain words.
- Check against sources. Limits such as those for stairs come from the relevant building codes and are reviewed when those codes change. Every calculation is checked with test cases before it goes live.
- Fair randomness. The wheel, dice, random numbers and team generator use the browser's cryptographic random generator, so every outcome has the same chance.
- Phone first. Every page is built for small screens and works without an app or an account.
Your data stays with you
All calculations run in your browser. Nothing you type, including name lists for the wheel, is sent to a server. The site is funded by clearly labelled ads; details are in the privacy policy.
Found a mistake or missing a tool?
If a tool gets something wrong or you need a calculator that isn't here yet, I'd like to hear from you. See the contact page.