50K Pace Chart
A 50K pace chart mapping finish times from 3:00 to 8:00 to the pace you need per km and per mile, with a note on why race-time prediction breaks down at ultra distance.
A 50K is 50 kilometres, or 31.0686 miles. A 5:00:00 finish needs 6:00 per kilometre (9:39 per mile), a 6:00:00 finish needs 7:12 per kilometre, and a 7:00:00 finish needs 8:24 per kilometre. The chart below covers every finish time from 3:00:00 to 8:00:00.
| Finish time | Pace / km | Pace / mile | Speed (kph) | Speed (mph) |
|---|---|---|---|---|
| 3:00:00 | 3:36 /km | 5:48 /mi | 16.7 | 10.4 |
| 3:10:00 | 3:48 /km | 6:07 /mi | 15.8 | 9.8 |
| 3:20:00 | 4:00 /km | 6:26 /mi | 15.0 | 9.3 |
| 3:30:00 | 4:12 /km | 6:46 /mi | 14.3 | 8.9 |
| 3:40:00 | 4:24 /km | 7:05 /mi | 13.6 | 8.5 |
| 3:50:00 | 4:36 /km | 7:24 /mi | 13.0 | 8.1 |
| 4:00:00 | 4:48 /km | 7:43 /mi | 12.5 | 7.8 |
| 4:10:00 | 5:00 /km | 8:03 /mi | 12.0 | 7.5 |
| 4:20:00 | 5:12 /km | 8:22 /mi | 11.5 | 7.2 |
| 4:30:00 | 5:24 /km | 8:41 /mi | 11.1 | 6.9 |
| 4:40:00 | 5:36 /km | 9:01 /mi | 10.7 | 6.7 |
| 4:50:00 | 5:48 /km | 9:20 /mi | 10.3 | 6.4 |
| 5:00:00 | 6:00 /km | 9:39 /mi | 10.0 | 6.2 |
| 5:10:00 | 6:12 /km | 9:59 /mi | 9.7 | 6.0 |
| 5:20:00 | 6:24 /km | 10:18 /mi | 9.4 | 5.8 |
| 5:30:00 | 6:36 /km | 10:37 /mi | 9.1 | 5.6 |
| 5:40:00 | 6:48 /km | 10:57 /mi | 8.8 | 5.5 |
| 5:50:00 | 7:00 /km | 11:16 /mi | 8.6 | 5.3 |
| 6:00:00 | 7:12 /km | 11:35 /mi | 8.3 | 5.2 |
| 6:10:00 | 7:24 /km | 11:55 /mi | 8.1 | 5.0 |
| 6:20:00 | 7:36 /km | 12:14 /mi | 7.9 | 4.9 |
| 6:30:00 | 7:48 /km | 12:33 /mi | 7.7 | 4.8 |
| 6:40:00 | 8:00 /km | 12:52 /mi | 7.5 | 4.7 |
| 6:50:00 | 8:12 /km | 13:12 /mi | 7.3 | 4.5 |
| 7:00:00 | 8:24 /km | 13:31 /mi | 7.1 | 4.4 |
| 7:10:00 | 8:36 /km | 13:50 /mi | 7.0 | 4.3 |
| 7:20:00 | 8:48 /km | 14:10 /mi | 6.8 | 4.2 |
| 7:30:00 | 9:00 /km | 14:29 /mi | 6.7 | 4.1 |
| 7:40:00 | 9:12 /km | 14:48 /mi | 6.5 | 4.1 |
| 7:50:00 | 9:24 /km | 15:08 /mi | 6.4 | 4.0 |
| 8:00:00 | 9:36 /km | 15:27 /mi | 6.3 | 3.9 |
Reading a 50K chart differently from a road chart
On a road marathon, average pace and running pace are close to the same thing. On a 50K they often are not. The pace column here is the arithmetic average across the whole 50 km, including every minute spent walking a climb and every minute spent at an aid station. If you plan to stop four times for two minutes, those eight minutes come out of the running, and the pace you have to hold while actually moving is faster than the chart row suggests.
The practical way to use this page is in reverse. Decide what average pace is realistic for the terrain, find it in the pace column, and read the finish time it produces. That is a more honest planning direction than picking a finish time first, particularly on a course with real climbing.
Why prediction breaks down past the marathon
The race time predictorand the equivalent-times tables elsewhere on this site use Riegel's formula, t2 = t1 x (d2 / d1) ^ 1.06. That model was fitted to endurance race performances and it works reasonably from 5K up to the marathon. At 50 km and beyond it starts to mislead, for reasons that have nothing to do with the exponent: ultras are frequently run on trail rather than road, they involve deliberate walking, they involve eating, and the variation between individuals in how well they hold pace past four hours is far larger than at marathon distance.
PaceLab therefore does not publish a predicted 50K time from a shorter race. The chart above is pure arithmetic, finish time divided by 50 km, and it is exact. Anything beyond that would be a number with more decimal places than confidence. The methodology page sets out the limits of the model in full.
Comparing a 50K with the marathon
A 50K is 7.805 km further than a marathon, which is roughly 18 percent more distance. Runners coming from the road often find the first 42 km familiar and the last 8 km entirely new. If you want to see what your marathon pace would produce over the shorter distance, the marathon pace chart covers 2:30 to 6:00, and the marathon goal pages break each of those into full splits. To plan a 50K segment by segment, the splits calculator accepts a custom distance.
Frequently asked questions
What pace do I need for a 5-hour 50K?
A 5:00:00 50K is 6:00 per kilometre, which is 9:39 per mile. That is the flat-road arithmetic; on a trail 50K with climbing, the moving pace needed to average that is considerably faster.
How long is a 50K in miles?
A 50 kilometre ultra is 31.0686 miles, which is about 4.85 miles further than a marathon. That extra distance is why the finish times on this chart start where the marathon chart ends.
Can I predict my 50K time from my marathon time?
Only loosely. Riegel's formula was fitted to endurance racing rather than to ultras, and beyond the marathon the assumptions behind it start to fail: terrain, aid-station stops, walking sections and fuelling all matter more than the exponent does. Treat any predicted 50K time as the fastest plausible outcome rather than a target.
Why is my 50K pace so much slower than my marathon pace?
Because most 50K races are not run on the flat sealed roads a marathon is. Climbing, descending, technical footing and time spent at aid stations all show up in the average pace this chart reports, even when you are running well.
More running calculators
Last reviewed . Formulas, constants and sources: methodology. Changes to any calculation are logged in the changelog.