Free tools

Tools

Little utilities we needed ourselves and could not find a version of that was free, fast and not covered in adverts. They all run entirely in your browser.

A/B Test Significance Calculator Paste in the visitors and conversions from two variants and find out whether the winner is real or is luck. Gives you the p-value, the statistical power and a confidence interval on the difference. Open the tool → Anagram Generator Type any phrase — a name, a quote, a spelling list — and get it back with the words scrambled, ready to print as a puzzle. Choose which words get jumbled and re-roll any of them. Open the tool →

What goes here

Small, single-purpose things: a calculator that does one job properly, a converter, a checker. The rules we hold them to are the ones we wanted from everybody else's version — free, no sign-up, no advert covering the answer, no limit on how many times you can use it, and the maths explained underneath rather than hidden.

Everything here runs in your own browser. Nothing you type into one of these tools is sent to us or to anyone else.

The list is short because it is honest: there is one tool on it. There will be more as we need them. If there is something you would find useful, tell us — the last few things on this site started that way.

Elsewhere on the site

If you came here for a calculator and stayed for something to do with your hands, the rest of Final Boss Games is daily puzzles and small browser games — a crossword, a cryptogram, a logic puzzle and a dozen others, new every morning, all free and all playable without an account. There are large-print editions of the printable ones, and a printable pack of the whole day.