Running Pace Calculator
Instant results as you type.
Your pace (per km, or per mile in miles)
5:30
Pace per km5:30
Pace per mile8:51
Speed (km/h or mph)10.91
Predicted 10 km57:20
Predicted half marathon2:06:30
Predicted marathon4:23:45
Predicted 5 km27:30
What this means5:30 per kilometre. The predictions use Riegel's formula and assume you have trained for the distance — a marathon time projected from a 5 km is optimistic without the endurance base behind it.
Pace is the language runners plan in, and this calculator converts a distance and a time into pace per kilometre and per mile, plus speed. It also projects what that performance implies at other race distances using Riegel's formula — with the caveat that a prediction assumes you have actually trained for the distance, which is where most optimistic marathon estimates come undone.
How to use it
- Enter the distance you ran and the time it took.
- Read your pace per kilometre and per mile.
- Compare the predicted times for 5 km, 10 km, half and full marathon.
Examples
- 5 km in 27:30 is 5:30 per kilometre, or 8:51 per mile.
- That predicts about 57:20 for 10 km and 2:06:30 for a half marathon.
Frequently asked questions
- How do I calculate my running pace?
- Divide total time by distance. A 5 km in 27 minutes 30 seconds is 1,650 seconds over 5 km, which is 330 seconds — 5:30 — per kilometre. Pace is more useful than speed for running because races and training targets are set in minutes per kilometre or mile.
- How reliable are the race predictions?
- They use Riegel's formula, a long-standing empirical fit that scales time by distance raised to about 1.06. It is reasonably good for adjacent distances — a 5 km predicting a 10 km — and increasingly optimistic as the gap widens. Predicting a marathon from a 5 km assumes an endurance base the 5 km never tested.
- What is a good 5 km time?
- It depends entirely on age, training history and sex, so comparisons to strangers are rarely useful. As rough context, many recreational runners finish between 25 and 35 minutes, club runners under 22, and elites under 15. The more useful comparison is with your own time three months ago.
- Should I train at my race pace?
- Only for part of the week. Most endurance programmes put the large majority of running at an easy, conversational pace and reserve race pace or faster for one or two sessions. Training hard every day is the most common way amateur runners stall — recovery is when the adaptation actually happens.