Speed converter
Convert speed between km/h, m/s, mph and knots.
Fill in the fields and the result will appear here automatically.
Converts speed between metres per second, kilometres per hour, miles per hour, knots and feet per second. Knots are used in sea and air navigation, miles per hour on US and UK road signs.
How it works
Formula and logic
Every unit converts through metres per second using exact factors.
Example
36 km/h is exactly 10 m/s and one knot is 1.852 km/h.
Fields and units
- Speed — in the selected source unit
- From unit — list option
- To unit — list option
How to use
- — Enter the value.
- — Pick the source unit.
- — Pick the target unit.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- BIPM: SI Brochure, version 4.01 (2026) NIST: conversion-factor tables, Appendix B.9
- Limitation
- The result is a rounded unit conversion. Check the entered value and selected units.
FAQ
What is a knot?
One nautical mile per hour, or 1.852 km/h. It is used in sea and air navigation.
Why is 36 km/h exactly 10 m/s?
Divide the numerical value in km/h by 3.6 to get m/s: 36/3.6 = 10. Multiply by 3.6 for the reverse conversion; the factor follows from 1000 metres and 3600 seconds.
Is the mph conversion exact?
Yes. The mile is defined as 1609.344 m, so one mph is exactly 0.44704 m/s.
Is it useful for running?
Running pace is usually minutes per kilometre — there is a separate pace calculator for that.