Why Speed Conversion Matters
Speed limits, vehicle specifications, and weather reports use different units depending on where you are. In the UK, road signs use miles per hour (MPH), while most other countries use kilometres per hour (KPH). Aviation and maritime use knots, and aviation often references Mach at high speeds.
The Conversion Formulas
MPH to KPH: Multiply by 1.609. For example, 70 MPH ≈ 113 KPH. KPH to MPH: Divide by 1.609. For example, 100 KPH ≈ 62 MPH. MPH to Knots: Multiply by 0.869. KPH to Knots: Multiply by 0.540. Mach 1: Approximately 767 MPH or 1,235 KPH at sea level (varies with altitude and temperature).
Use Our Converter
Try our unit converter — select speed to instantly convert between MPH, KPH, knots, and Mach.