Running Pace Calculator
One number to train by — your pace per kilometre, and the race times it points to.
Enter any distance and finish time to get your pace in minutes per kilometre and your speed in km/h, see the even splits to hold, and predict your 5K, 10K, half marathon and marathon times with the Riegel formula — all in metric.
Pace, speed, splits and race predictions from your distance and time. Predictions assume similar conditions and consistent training — use them as a target, not a guarantee.
How pace and speed are worked out
Pace is time divided by distance
Your pace is how long it takes to cover one kilometre: convert your finish time to minutes, divide by the distance in kilometres, and express the result as minutes and seconds per kilometre. Your speed is the mirror image — distance divided by time — usually shown in kilometres per hour. The two describe the same run from different angles: a lower pace and a higher speed both mean you are running faster.
From pace to race predictions
Once the calculator knows your pace over one distance it can estimate others using Peter Riegel's formula: T2 = T1 × (D2 ÷ D1)^1.06. The 1.06 exponent captures a simple truth — you cannot hold your 5K pace for a marathon, so predicted pace slows a little as the distance grows.
Worked example
Run 5 km in 25:00 and your pace is 25 ÷ 5 = 5:00 per kilometre, a speed of 12 km/h. Feed that into Riegel and it predicts roughly 52:00 for 10K, about 1:55 for a half marathon and around 3:59 for a marathon — the times to aim for if your training supports them.
Predictions are targets, not promises. They assume similar terrain, weather and fitness across distances, and they reward consistent training. Heat, hills, wind and how well you have trained for the specific distance all move the real result.
Predicting your 5K, 10K, half and marathon times
The Riegel formula turns one honest race result into estimates for every other distance. It works best when you feed it a recent, all-out effort rather than an easy training run, and when your training actually covers the target distance.
- Shorter is faster. Your per-kilometre pace over 5K will always be quicker than your marathon pace — the formula builds that slowdown in.
- Longer races need specific training. A great 5K predicts a marathon time only if you have done the long runs; without the endurance base, the real marathon will be slower.
- Conditions matter. A hot, humid day or a hilly course can add minutes the formula never sees.
- Use it to set pace. The most useful output is the goal pace per kilometre to hold on race day, which the even-splits view makes concrete.
Re-run the numbers whenever you set a new personal best over any distance — the predictions sharpen as your fitness data gets fresher.
Even splits, negative splits and pacing a race
What a split is
A split is your time for one segment of the run — usually each kilometre. Even splits means every segment takes the same time; that steady effort is what this calculator shows, and it is the pace to rehearse in training so it feels controlled on the day.
Even vs negative splits
A negative split runs the second half slightly faster than the first. For most distance races this beats going out hard, because a too-fast start spends energy you cannot recover. Aim to hold goal pace — or a touch slower — through the first half, then lift the effort over the closing kilometres if you still feel strong.
Banking a buffer
Because races rarely go exactly to plan, many runners target a pace a few seconds per kilometre quicker than the bare minimum for their goal time. For a sub-2-hour half (21.1 km in 120 minutes, about 5:41/km), practising around 5:35/km gives a small cushion for a slow kilometre or a hill without blowing up.
❓ Frequently asked Frequently asked questions
How do I calculate running pace?
Pace is simply time divided by distance. Convert your finish time to minutes, divide by the distance in kilometres, and you get your pace in minutes per kilometre. For example, 25 minutes over 5 km is 25 ÷ 5 = 5:00 per kilometre. Speed is the other way round — distance divided by time — so 5 km in 25 minutes (0.4167 hours) is 12 km/h. This calculator does both for you and also shows even splits and predicted race times.
How can I predict my race time?
A common method is Peter Riegel's formula: T2 = T1 × (D2 ÷ D1)^1.06, where T1 is a time you have already run over distance D1 and D2 is the new distance. The 1.06 exponent reflects that pace slows a little as distance grows. From a 25:00 5K it predicts roughly 52:00 for 10K, about 1:55 for a half marathon and around 3:59 for a marathon. Predictions assume similar conditions and consistent training, so treat them as a well-informed target rather than a guarantee.
What is a good 5K pace?
It depends entirely on your age, fitness and experience, so "good" is personal. As rough context, many recreational runners finish a 5K somewhere between 25 and 35 minutes, which is about 5:00 to 7:00 per kilometre; a sub-25-minute 5K (5:00/km) is a popular milestone, and well-trained club runners go under 20 minutes (4:00/km). The most useful benchmark is your own recent times — aim to improve on those rather than chase someone else's number.
What pace do I need for a sub-2-hour half marathon?
A half marathon is 21.1 km, so finishing in under 2 hours (120 minutes) means averaging about 5:41 per kilometre, or roughly 10.6 km/h. Because racing rarely goes perfectly to plan, most runners aim a few seconds per kilometre faster than the exact target to bank a small buffer — around 5:35/km — and practise that pace in training so it feels controlled on race day.
Should I run even or negative splits?
Even splits mean running each segment at the same pace; negative splits mean running the second half slightly faster than the first. For most distance races, even or gently negative splits produce the best result because starting too fast burns energy you cannot get back. A good approach is to hold your goal pace — or a touch slower — for the first half, then lift the effort over the closing kilometres if you feel strong. This calculator shows even splits so you can see the steady pace to aim for.
Where these figures come from
The maths here is standard running arithmetic, not a country-specific rule, so it applies wherever you run. The one estimate — race prediction — uses a long-established formula that any runner can check against their own results.
- Pace — finish time divided by distance, expressed as minutes and seconds per kilometre.
- Speed — distance divided by time, in kilometres per hour.
- Race prediction — Peter Riegel's formula, T2 = T1 × (D2 ÷ D1)^1.06, first published in the 1970s and still widely used to estimate equivalent times across distances.
- Standard distances — 5 km, 10 km, half marathon (21.0975 km) and marathon (42.195 km).
Last checked: July 2026. Race predictions assume similar conditions and consistent training, and real results vary with terrain, weather, pacing and how specifically you have trained for the distance. Build up mileage sensibly, and if you are new to running or have a health condition, check with a doctor before starting a hard training block.
Select the question that matches where you are right now.
The headline number is your pace — minutes and seconds per kilometre. The breakdown adds your speed in km/h, the even splits to hold, and predicted finish times for the standard race distances.
Use your pace as the target to rehearse in training so it feels controlled on race day, and the even splits as the rhythm to lock into from the start line.
The predictions are estimates, not guarantees. They assume similar conditions and that your training covers the target distance — a great 5K only becomes a great marathon with the long runs behind it.
They are the same run described two ways: a lower pace per kilometre and a higher speed in km/h both mean faster. Pick whichever your watch or treadmill shows.
Four things move your real race time the most: the distance, your training, the conditions and how you pace the effort.
Pace slows as distance grows — the Riegel exponent of 1.06 builds that in, so your marathon pace is never your 5K pace.
Heat, humidity, hills and wind all add time the formula cannot see. Adjust your goal on a tough day rather than chasing the prediction.
Predictions reward consistent training over the target distance, and a controlled, even or gently negative split protects the time you have earned.
A few reliable habits lower your pace over time without risking injury.
Most training should be at a comfortable, conversational pace. Easy volume builds the engine that faster running draws on.
One or two faster sessions a week — intervals or a tempo run — teach your legs and lungs to hold a quicker pace.
Increase distance and intensity slowly and take rest days. Steady, injury-free progression beats big jumps that force time off.
Pace is one piece of the picture. Explore the rest of your health numbers with these related calculators.