MPH to KMH Converter — Miles to Kilometers Speed
Convert miles per hour to kilometers per hour instantly with our free speed converter. Useful for driving, weather reports, athletics, and speedometers.
Formula: km/h = mph × 1.60934
MPH to KMH Conversion Table
| MPH | KMH |
|---|---|
| 30 mph | 48.280 km/h |
| 60 mph | 96.561 km/h |
| 100 mph | 160.93 km/h |
Formula
km/h = mph × 1.60934
Example: 30 mph = 48.280 km/h
Frequently Asked Questions
Looking for the reverse? KMH to MPH Converter
About speed conversion
Speed conversion between km/h, mph, m/s, and knots is essential for driving across borders, reading aviation or maritime reports, and interpreting sports statistics. The metric km/h and m/s differ by a simple factor of 3.6, while the mph used in the US and UK is about 1.6× the equivalent km/h. Knots (nautical miles per hour) add a third system used by ships and aircraft — one knot equals 1.852 km/h exactly.
How the math works
Speed is just distance ÷ time, so unit conversion follows from length and time conversions. 1 km/h = 0.27778 m/s (divide by 3.6), 1 mph = 1.609344 km/h, 1 knot = 1.852 km/h = 1.15078 mph. The math is straightforward multiplication, but the mental approximation (mph ≈ km/h × 0.6) is only 3% off and useful for quick estimates.
When you'll use this conversion
- Driving abroad — interpreting speed limit signs
- GPS and navigation apps
- Aviation — aircraft speed in knots
- Marine navigation and boating
- Sports statistics (serve speed in tennis, pitch speed in baseball)
- Weather reports (wind speed in km/h, mph, or knots depending on country)
A bit of history
The knot originates from a Dutch practice of measuring ship speed by throwing a rope with knots tied at intervals overboard and counting how many passed in a fixed time. One knot corresponds to one nautical mile per hour, and the nautical mile itself equals exactly one minute of latitude — about 1.852 km. This tie to the Earth's geometry is why aviation and maritime industries still prefer knots.
Common mistakes
- Assuming 100 km/h = 100 mph — the actual equivalent is about 62 mph
- Confusing km/h with m/s by a factor of 3.6 in physics problems
- Using statute miles per hour when knots are required on boats or aircraft
- Forgetting that Mach (speed of sound) varies with altitude and temperature
Quick tips
- Rough mental conversion: mph × 1.6 ≈ km/h; km/h × 0.6 ≈ mph
- Running pace: 4 min/km ≈ 15 km/h ≈ 9.3 mph
- Highway speeds around the world — 100 km/h ≈ 62 mph is common on EU motorways