How pace is calculated
Pace is the time it takes to cover one unit of distance. Divide your total time by your distance in kilometres to get the pace per kilometre, or by the distance in miles for the pace per mile. Speed is the opposite measure: the distance you cover per hour.
Example
Running 10 km in 50 minutes gives a pace of 5:00 per kilometre, which is about 8:03 per mile and a speed of 12 km/h.
Finish times at the same pace
The race predictions multiply your pace by the distance of a 5K, 10K, half marathon (21.0975 km) and marathon (42.195 km). They assume you keep exactly the same pace, which is realistic for the shorter distances but optimistic for longer ones, because fatigue slows most runners.
Pacing tips
- Start a little slower than your target pace and finish stronger.
- Build mileage gradually, by no more than about 10% per week.
- Use easy runs to build endurance and only a few harder sessions per week.
Frequently asked questions
Why are predicted marathon times optimistic?
Because the calculator assumes you can hold the same pace for the whole distance, which is difficult beyond about 15 km without specific training.
How do I convert min/km to min/mile?
Multiply the pace per kilometre by 1.609.
Can I use it for walking or cycling?
Yes, enter the distance and time. Speed is usually more useful for cycling.