Speed, time and distance
Enter any two values and the third is calculated instantly: speed in km/h, mph or m/s, time in hours, minutes and seconds, distance in kilometers. With running pace per km and per mile.
The formula: speed = distance ÷ time
All three quantities are tied together by a single formula that can be rearranged three ways: speed = distance ÷ time, distance = speed × time, time = distance ÷ speed. To convert m/s to km/h you multiply by 3.6 (10 m/s is therefore 36 km/h), and one mile per hour equals 1.609 km/h — so a 60 mph highway speed limit is about 96.6 km/h. This tool handles all the conversions for you: just pick whichever unit you prefer from the menu.
Running pace per km and per mile
Runners don't think in km/h or mph — they think in minutes per kilometer or per mile. A classic example: 10 km in 50 minutes means a speed of 12 km/h, i.e. a pace of 5:00 per km (about 8:03 per mile). To run a half marathon (13.1 miles / 21.097 km) under 2 hours you need to hold at least 9:09 per mile (5:41 per km), and a marathon under 4 hours takes roughly the same steady pace over 26.2 miles. Enter your goal distance and target time and instantly see the pace to hold in your race or workout.