Is it safe to use the Length Converter online?

Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.

Are my files uploaded to a server?

No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.

Do I need to sign up or pay?

No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.

How accurate is this?

Conversions use IEEE-754 double precision with the international yard (1959) at 0.9144 m exactly. Accurate to ~15 significant figures.

Why does cm to inches show 0.393701?

Because 1 cm = 1/2.54 inches exactly = 0.393700787…

Length Converter

Convert between every common length unit at once. Type a value in any unit and watch the rest update live — millimetres, centimetres, metres, kilometres, inches, feet, yards, miles. No rounding surprises.

Features

13 units side-by-side: mm, cm, m, km, in, ft, yd, mi, nautical mile, μm, nm, mil, light-year
Edit any cell — every other unit recalculates instantly
Tabular display with copy-on-click for each value
Switchable precision (3 / 6 / 9 significant figures)
Recent conversions saved locally

How to length converter

Type in any unit — Pick the unit you know and type — others convert automatically.
Copy the unit you need — Click any value to copy it to clipboard.
Bookmark for daily use — Save the URL — it works offline.

Frequently asked questions

Is it safe to use the Length Converter online?: Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.
Are my files uploaded to a server?: No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.
Do I need to sign up or pay?: No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.
How accurate is this?: Conversions use IEEE-754 double precision with the international yard (1959) at 0.9144 m exactly. Accurate to ~15 significant figures.
Why does cm to inches show 0.393701?: Because 1 cm = 1/2.54 inches exactly = 0.393700787…