Running calculator: pace, time, distance and race prediction
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This running calculator answers the questions runners ask most before a race and during a training block: which pace gives the finish time you want, how long a distance takes at a given pace, which splits to hold on the course and what result is realistic over another distance. Enter two values and the third is calculated. Pace is entered in minutes per kilometre or per mile, with speed in km/h or mph shown next to it. The calculator runs in your browser, needs no account and stores nothing.
Coaches use the same numbers when they plan for an athlete: goal race pace, the pace of repetitions and the expected result after a training block. The formulas are simple and open, and we describe them below together with their limits.
How to use the running pace calculator
Choose what you want to calculate. When you know the distance and the time, the calculator gives you the pace and speed. When you know the distance and the pace, it gives your finish time. When you know the time and the pace, it gives the distance covered. Race distances are ready to pick: 5K, 10K, half marathon (21.0975 km) and marathon (42.195 km), and you can type any other distance by hand.
Splits show where you should be on the course at an even pace: every kilometre or mile, and every 5 km in the marathon so the table stays readable. Even pacing is the safest strategy over long distances for most runners, so splits are a good reference on your watch.
The "Copy link to result" button saves the values in the page address. Send it to an athlete or a club mate, and the calculator shows the same result when they open it.
Race time prediction from another distance
The prediction uses the formula Peter Riegel published in 1977: the time over the new distance equals the known time multiplied by the ratio of the distances raised to the power of 1.06. Example: a 40:00 10K predicts a half marathon of about 1:28:15 and a marathon of about 3:04.
The formula also works the other way. If your goal is a 3:30 marathon, the calculator shows which 5K, 10K and half marathon results match that goal. For a 3:30 marathon that is about 45:40 for 10K. It is a good check halfway through a build: a 10K tune-up race tells you more than how a training run felt.
The prediction assumes you are similarly prepared for both distances. For the marathon it is usually optimistic, because a short race does not test endurance, fuelling on the course or muscle fatigue after 30 kilometres. A runner with low weekly mileage should treat it as an upper limit, not a race plan.
Next to the prediction there is a "Calculate training paces from this result" button. It carries the distance and time to the training paces page, where the same result gives you easy, marathon, threshold, interval and repetition paces.
Running pace tables
The first table lists paces from 3:00 to 8:00 min/km in 15-second steps, with speed in km/h and the finish time over four race distances at an even pace. The second does the same from 5:00 to 13:00 min/mile, with speed in mph. Use them to check quickly which pace matches a given result without typing anything.
| Pace (min/km) | Speed (km/h) | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|
| 3:00 | 20.0 | 15:00 | 30:00 | 1:03:17 | 2:06:35 |
| 3:15 | 18.5 | 16:15 | 32:30 | 1:08:34 | 2:17:08 |
| 3:30 | 17.1 | 17:30 | 35:00 | 1:13:50 | 2:27:40 |
| 3:45 | 16.0 | 18:45 | 37:30 | 1:19:06 | 2:38:13 |
| 4:00 | 15.0 | 20:00 | 40:00 | 1:24:23 | 2:48:46 |
| 4:15 | 14.1 | 21:15 | 42:30 | 1:29:39 | 2:59:19 |
| 4:30 | 13.3 | 22:30 | 45:00 | 1:34:56 | 3:09:52 |
| 4:45 | 12.6 | 23:45 | 47:30 | 1:40:12 | 3:20:25 |
| 5:00 | 12.0 | 25:00 | 50:00 | 1:45:29 | 3:30:58 |
| 5:15 | 11.4 | 26:15 | 52:30 | 1:50:45 | 3:41:31 |
| 5:30 | 10.9 | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 5:45 | 10.4 | 28:45 | 57:30 | 2:01:18 | 4:02:37 |
| 6:00 | 10.0 | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:15 | 9.6 | 31:15 | 1:02:30 | 2:11:51 | 4:23:43 |
| 6:30 | 9.2 | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 6:45 | 8.9 | 33:45 | 1:07:30 | 2:22:24 | 4:44:48 |
| 7:00 | 8.6 | 35:00 | 1:10:00 | 2:27:40 | 4:55:21 |
| 7:15 | 8.3 | 36:15 | 1:12:30 | 2:32:57 | 5:05:54 |
| 7:30 | 8.0 | 37:30 | 1:15:00 | 2:38:13 | 5:16:27 |
| 7:45 | 7.7 | 38:45 | 1:17:30 | 2:43:30 | 5:27:00 |
| 8:00 | 7.5 | 40:00 | 1:20:00 | 2:48:46 | 5:37:33 |
| Pace (min/mile) | Speed (mph) | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|
| 5:00 | 12.0 | 15:32 | 31:04 | 1:05:32 | 2:11:05 |
| 5:15 | 11.4 | 16:18 | 32:37 | 1:08:49 | 2:17:38 |
| 5:30 | 10.9 | 17:05 | 34:10 | 1:12:06 | 2:24:12 |
| 5:45 | 10.4 | 17:51 | 35:43 | 1:15:22 | 2:30:45 |
| 6:00 | 10.0 | 18:38 | 37:16 | 1:18:39 | 2:37:18 |
| 6:15 | 9.6 | 19:25 | 38:50 | 1:21:56 | 2:43:52 |
| 6:30 | 9.2 | 20:11 | 40:23 | 1:25:12 | 2:50:25 |
| 6:45 | 8.9 | 20:58 | 41:56 | 1:28:29 | 2:56:58 |
| 7:00 | 8.6 | 21:44 | 43:29 | 1:31:45 | 3:03:31 |
| 7:15 | 8.3 | 22:31 | 45:02 | 1:35:02 | 3:10:05 |
| 7:30 | 8.0 | 23:18 | 46:36 | 1:38:19 | 3:16:38 |
| 7:45 | 7.7 | 24:04 | 48:09 | 1:41:35 | 3:23:11 |
| 8:00 | 7.5 | 24:51 | 49:42 | 1:44:52 | 3:29:45 |
| 8:15 | 7.3 | 25:37 | 51:15 | 1:48:09 | 3:36:18 |
| 8:30 | 7.1 | 26:24 | 52:48 | 1:51:25 | 3:42:51 |
| 8:45 | 6.9 | 27:11 | 54:22 | 1:54:42 | 3:49:24 |
| 9:00 | 6.7 | 27:57 | 55:55 | 1:57:59 | 3:55:58 |
| 9:15 | 6.5 | 28:44 | 57:28 | 2:01:15 | 4:02:31 |
| 9:30 | 6.3 | 29:30 | 59:01 | 2:04:32 | 4:09:04 |
| 9:45 | 6.2 | 30:17 | 1:00:35 | 2:07:48 | 4:15:37 |
| 10:00 | 6.0 | 31:04 | 1:02:08 | 2:11:05 | 4:22:11 |
| 10:15 | 5.9 | 31:50 | 1:03:41 | 2:14:22 | 4:28:44 |
| 10:30 | 5.7 | 32:37 | 1:05:14 | 2:17:38 | 4:35:17 |
| 10:45 | 5.6 | 33:23 | 1:06:47 | 2:20:55 | 4:41:51 |
| 11:00 | 5.5 | 34:10 | 1:08:21 | 2:24:12 | 4:48:24 |
| 11:15 | 5.3 | 34:57 | 1:09:54 | 2:27:28 | 4:54:57 |
| 11:30 | 5.2 | 35:43 | 1:11:27 | 2:30:45 | 5:01:30 |
| 11:45 | 5.1 | 36:30 | 1:13:00 | 2:34:02 | 5:08:04 |
| 12:00 | 5.0 | 37:16 | 1:14:33 | 2:37:18 | 5:14:37 |
| 12:15 | 4.9 | 38:03 | 1:16:07 | 2:40:35 | 5:21:10 |
| 12:30 | 4.8 | 38:50 | 1:17:40 | 2:43:52 | 5:27:44 |
| 12:45 | 4.7 | 39:36 | 1:19:13 | 2:47:08 | 5:34:17 |
| 13:00 | 4.6 | 40:23 | 1:20:46 | 2:50:25 | 5:40:50 |
Other calculators
The pace calculator is the first step. Turn a race result into training paces. Turn a threshold test and your heart rate into heart rate zones, and your threshold pace into pace zones. The zones come from the same library the EasyTrackly app uses, so they match the athlete's settings to the beat and to the second.
Frequently asked questions
How do I convert pace to speed?
Divide 60 by the pace written in minutes. A pace of 5:00 min/km is 5 minutes, so the speed is 60 / 5 = 12 km/h. A pace of 4:30 min/km is 4.5 minutes, or 13.3 km/h. The other way round: 60 divided by speed gives pace in minutes, and you multiply the decimal part by 60 to get seconds.
What pace do I need for a 4-hour marathon?
About 5:41 min/km or 9:09 min/mile, a little over 10.5 km/h. Because the distance you actually run is usually longer than 42.195 km, many runners plan a few seconds per kilometre faster. A pace of 5:00 min/km gives a 3:30:58 marathon.
Is a marathon prediction from a 10K reliable?
It is a good starting point, not a guarantee. The Riegel formula predicts results between 5K and the half marathon well. For the marathon it is usually a few minutes too optimistic, especially for runners who run less than about 30 miles a week or have not done long runs.
What is threshold pace?
It is the fastest pace a well-trained runner can hold for about an hour. For most amateurs it sits between 10K pace and half marathon pace. You can find it from a race result on the training paces page or with a 30-minute test on the heart rate zones page.
Does the calculator work in miles?
Yes. The unit switch changes the fields and the result to minutes per mile and miles per hour. The link to the result remembers the unit you chose.