I've been annoyed by unit conversion sites for years. They're slow, covered in ads, and half of them require JavaScript frameworks just to multiply a number by 2.54.
So I built a dead-simple unit converter — no ads, no tracking, no frameworks. Just a single HTML file that does the math instantly.
What it converts
- Length: mm, cm, m, km, in, ft, yd, mi
- Weight: mg, g, kg, t (metric tons), oz, lb
- Temperature: Celsius, Fahrenheit, Kelvin
- Volume: mL, L, tsp, tbsp, fl oz, cup, pt, qt, gal
- Area: cm², m², km², in², ft², ac, mi²
- Speed: m/s, km/h, mph, knots
- Data: bits, bytes, KB, MB, GB, TB
It also includes a data size converter, which I couldn't find anywhere as a standalone tool without it being buried 3 clicks deep.
Why no framework?
The whole thing is ~400 lines of vanilla HTML/CSS/JS. Loads in under 100ms even on a slow connection. No npm, no build step, no dependencies. Just open it and it works — including offline once cached.
I'm old enough to remember when the web was like this everywhere. Trying to bring that back, one tiny tool at a time.
Try it
billion-unitconverter.pages.dev
Type a value, pick a category and unit, and the conversions appear instantly. No submit button. No loading spinner.
Source is a single HTML file if you want to fork it or host it yourself.
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