CalcBin

CalcBin is one big toolbox of free online tools: converters, calculators, and generators, all on one site with no signup. Need to convert kilograms to pounds, turn JSON into CSV, make a QR code, generate a password, or work out a mortgage payment? It is probably already there.

It started because the author was fed up with sketchy converter sites covered in ads, so they just built their own — 177 tools at first, shown on Hacker News in February 2026. The collection keeps growing: the homepage now lists 218 tools, counted on 8 November 2026.

There is something for developers — Base64, JSON to TypeScript, cron expression and regex generators, JWT tools — and plenty for everyday life too: cooking converters, shoe sizes, tip and bill splitting, BMI, pregnancy and retirement calculators. Everything runs in the browser, free.

It is a solo utility site, not a company product, so expect simple single-purpose pages rather than accounts, history, or saved settings. For the one-off job you need right now, that is exactly the point.