Length Converter
A fast, private length converter. Pick your units, type a value, and the conversion appears instantly — in either direction. Everything runs on your device, so nothing you enter is ever uploaded.
- 🔒 100% private — no uploads
- 🆓 Free, no watermark
- 📱 Works on any device
How to convert
- 1
Choose your units
The tool opens on the most common pairing. Change either unit from its dropdown, or hit the swap button to flip the direction.
- 2
Type a value
Enter a number in either box. The other side updates instantly as you type — convert either way without pressing a button.
- 3
Copy or compare
Copy the result to your clipboard, or scan the common-values table below for quick at-a-glance conversions.
Why use Length Converter?
100% private
Every conversion is computed locally in your browser. Nothing you enter ever leaves your device.
Instant & two-way
Results update live as you type, in either direction — no “convert” button and no page reloads.
Accurate
Conversions use exact, standards-based factors, so you get the same answer a trusted reference would.
Works on any device
No install and no account — it runs in any modern browser on desktop, tablet or phone.
From millimeters to miles
The length converter covers the metric ladder (mm, cm, m, km) and the imperial set (inches, feet, yards, miles) with exact factors — the inch has been defined as exactly 2.54 cm since 1959. Type in either box and the other updates live, in both directions.
The conversions people actually need
Heights (170 cm ↔ 5 ft 7 in), screens (a 27-inch monitor is 68.6 cm diagonally), DIY measurements (a 8 ft board is 2.44 m) and race distances (10 km is 6.2 miles). For the most-searched pairs, see the dedicated cm→inches and miles→km pages with worked formulas.
Frequently asked questions
What units does the length converter support?
It covers the common length units (mm, cm, m, km, in, ft, yd, mi and others). Choose any two from the dropdowns and convert between them instantly.
Does anything get uploaded to a server?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is uploaded, stored or logged, and it keeps working offline once the page has loaded.
Is it free?
Yes — completely free, with no account, no watermark and no limits on how much you convert.