Convert km/h to mph
Instant, precise speed conversions between kilometers per hour and miles per hour.
Enter a value and choose units to convert between km/h and mph. The calculator uses the exact factor 1 km/h = 0.6213711922 mph.
kilometer/hour (km/h)
mile/hour (mph)
Uses exact factors: 1 km/h = 0.6213711922 mph, 1 mph = 1.609344 km/h.
Kilometer per hour (km/h)
Definition: The kilometer per hour (km/h) expresses how many kilometers are traveled in one hour. It is derived from the kilometer (distance) and hour (time).
Usage: Km/h is the standard speed unit on road signs and vehicle speedometers in most countries using the metric system, and is widely applied for driving speeds, cycling speeds, and wind speeds.
Quick fact: 100 km/h is a common highway speed limit and equals about 62.137 mph.
Mile per hour (mph)
Definition: The mile per hour (mph) expresses how many international miles are traveled in one hour.
Usage: Mph is standard on road signs and dashboards in the United States, the United Kingdom, and a few other regions, and is also common in automotive and aviation contexts.
Exact relation: 1 mph = 1.609344 km/h (the precise inverse of 1 km/h = 0.6213711922 mph).
How to Convert km/h to mph (and mph to km/h)
To convert kilometers per hour to miles per hour, multiply the speed in km/h by
0.6213711922 .
Formula (km/h → mph): mph = km/h × 0.6213711922
Formula (mph → km/h): km/h = mph × 1.609344
Example: 90 km/h × 0.6213711922 ≈ 55.923 mph (often rounded to 55.9 mph).
Kilometer/hour to Mile/hour Conversion Table
| Kilometer/hour (km/h) | Mile/hour (mph) |
|---|
Table values (when populated) are typically rounded to 6 decimal places for readability.