Pace calculator: work out pace, time and distance
Work out pace, finish time or distance. You also get your speed in km/h, splits and a prediction for 5K to marathon.
What do you want to calculate?
Enter distance and time to get your pace, speed and splits.
Enter distance and pace to get your finish time and the splits for it.
Enter time and pace to see how far you get in that time.
Type only the digits and the colons are added for you. 4500 becomes 45:00, 13000 becomes 1:30:00.
Result
Splits
Race time prediction
Extrapolated with the Riegel formula. This holds if your input is a recent race result and you have trained for the target distance.
How the pace calculator works
Pace, time and distance
Pace = time ÷ distance
Pace is the number of minutes you need for one kilometre (or one mile). Any two of the three values give you the third, so time = pace × distance and distance = time ÷ pace. Example: 10 km in 45:00 gives a pace of 4:30 min/km.
Converting pace to km/h
km/h = 60 ÷ pace (in minutes)
A pace of 4:30 min/km is 4.5 minutes per kilometre, so 60 ÷ 4.5 = 13.33 km/h. For pace per mile, multiply your pace per kilometre by 1.609.
Race time prediction using Riegel’s formula
T₂ = T₁ × (D₂ ÷ D₁)1,06
In the late 1970s, engineer and marathon runner Peter Riegel described how much pace drops as the distance gets longer. T₁ is your time over distance D₁, T₂ the predicted time over D₂. The exponent 1.06 reflects that you get slightly slower over longer distances. Example: 10 km in 45:00 predicts a half marathon of 45:00 × (21.0975 ÷ 10)^1.06 ≈ 1:39:17.
Tips for your race pace
Even rather than too fast
The most common race mistake is starting too fast. Even 5 to 10 seconds per kilometre quicker than your target pace often costs you far more time in the second half than you gained early on. Run the first kilometres deliberately under control.
Negative splits for long races
With a negative split, the second half is faster than the first. The calculator runs the second half about 2% faster and keeps the same finish time. It works well in the half marathon and marathon because you waste less energy early on.
Pace in training
Not every run should be at race pace. Easy runs are usually 60 to 90 seconds per kilometre slower than your 10K pace. The most accurate way to find your personal threshold is a threshold test, for example with the critical speed calculator.
Course, weather and GPS
Hills, heat and wind cost time. Run by feel then, not strictly by pace. In races, GPS watches often measure a little more than the official distance because you can’t always run the racing line. So go by the kilometre markers and your splits.
Pace chart: finish times from 5K to marathon
The chart shows finish times at an even pace. Find your target time and read the pace on the left.
Pace calculator FAQ
How do I calculate my pace?
Divide your time by the distance. 10 km in 50 minutes gives 50 ÷ 10 = 5 minutes per kilometre, so a pace of 5:00 min/km. Convert seconds into minutes first, 45:30 is 45.5 minutes. The pace calculator does this for you and also works out time or distance from the other two values.
How do I convert min/km to km/h?
Divide 60 by your pace in minutes. 5:00 min/km is 60 ÷ 5 = 12 km/h, 4:30 min/km is 60 ÷ 4.5 = 13.33 km/h. The other way round, 60 divided by your speed in km/h gives your pace in minutes per kilometre.
How do I convert min/km to min/mile?
One mile is 1.609 km, so multiply your pace per kilometre by 1.609. 5:00 min/km becomes 8:02 min/mile, 4:00 min/km becomes 6:26 min/mile. In the calculator, switch the unit to miles at the top.
What is a good pace for 10K?
That depends on age, experience and training. Many beginners run 10K at 6:00 to 7:00 min/km, finishing in 60 to 70 minutes. Keen club runners break 50 minutes with a pace under 5:00 min/km, and very good amateurs run under 4:00 min/km, finishing under 40 minutes. Compare yourself mainly with your own times from the last few months.
What pace do I need for a sub-4-hour marathon?
For 3:59:59 you need to average 5:41 min/km, for under 3:30 hours 4:58 min/km and for under 3 hours 4:15 min/km. Allow a few seconds of buffer per kilometre, because bends and aid stations usually mean you run a little more than 42.195 km.
How accurate is the race time prediction?
The prediction uses Peter Riegel’s formula and is fairly reliable for neighbouring distances, such as from 10K to the half marathon. The further apart the two distances are, the less accurate it gets. A marathon time predicted from a 5K race often comes out too fast, because it assumes the right endurance training. Ideally, use a recent race result over a distance close to your goal.
What does negative split mean?
With a negative split, you run the second half of a race faster than the first. You start a little easier and pick up the pace towards the end. Many personal bests over long distances are run this way. The “Negative split” option in the calculator shows you the splits for it with the same finish time.