About

This site collects small, single-purpose tools for jobs that usually mean installing desktop software or uploading files to an unknown converter. Every tool here runs as JavaScript in your browser tab: files are read, processed and saved on your own device.

The calculators show their formulas and are tested against published reference data (for example, the CIEDE2000 test pairs of Sharma, Wu and Dalal, and standard Erlang tables).

The ZIP and EPUB tools use the open-source zip.js library (BSD-3-Clause, see license).

Found a bug or a file that doesn’t work? The tools are built and maintained by a small independent developer; reports help.