Speed Converter
A fast, private speed 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 Speed 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.
km/h, mph, knots and meters per second
Speed units are length over time, so the factors mirror the distance ones: 1 mph = 1.609 km/h, and a knot (one nautical mile per hour) is 1.852 km/h. Meters per second — the scientific unit — is 3.6 km/h, handy for converting wind speeds in weather data.
Reading foreign speed limits
A 130 km/h European motorway limit is 81 mph; a US 65 mph limit is 105 km/h. Aviation and sailing quote knots (150 kn ≈ 278 km/h ≈ 173 mph), and running apps mix min/km with mph treadmills — this converter puts them all on one scale.
Frequently asked questions
What units does the speed converter support?
It covers the common speed units (m/s, km/h, mph, ft/s, kn 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.