20K Pace Calculator
8:03/mi
7.46mph
20.000 km · ~12.43 mi
- First half
- 8:03/mi
- Second half
- 8:03/mi
- 10K split
- 50:00
Checkpoints
5K
3.11 mi
10K
6.21 mi
15K
9.32 mi
Finish
12.43 mi
Kilometer splits
1 km
1.00 km
2 km
2.00 km
3 km
3.00 km
4 km
4.00 km
5 km
5.00 km
6 km
6.00 km
7 km
7.00 km
8 km
8.00 km
9 km
9.00 km
10 km
10.00 km
11 km
11.00 km
12 km
12.00 km
13 km
13.00 km
14 km
14.00 km
15 km
15.00 km
16 km
16.00 km
17 km
17.00 km
18 km
18.00 km
19 km
19.00 km
20 km
20.00 km
Mile splits
1 mi
1.00 mi
2 mi
2.00 mi
3 mi
3.00 mi
4 mi
4.00 mi
5 mi
5.00 mi
6 mi
6.00 mi
7 mi
7.00 mi
8 mi
8.00 mi
9 mi
9.00 mi
10 mi
10.00 mi
11 mi
11.00 mi
12 mi
12.00 mi
Finish
12.43 mi
Same pace, longer race
Half marathon
13.11 mi at this pace
Even pace for 20.000 km, not a race-equivalence predictor. The half marathon row is this pace held for 21.0975 km, not a prediction. 10K pace · 15K pace · 10 mile pace · half marathon pace · race time predictor · race pace band.
Worked examples
1:40:00 20K
8:03 /mi · 5:00 /km · 10K 50:00
1:20:00 20K
6:26 /mi · 4:00 /km · 10K 40:00
2:00:00 20K
9:39 /mi · 6:00 /km · 10K 1:00:00
Who runs a 20K
The 20K is a less common road distance than the 10K or half marathon, but a number of long-running road races use it, and it sits naturally in a half-marathon build: 20 km is only 1.0975 km short of 13.1 miles. Many runners use one as a goal-pace rehearsal a few weeks out, to test shoes, fueling, and pacing without the full race load. Outside road running, 20 km is also a standard championship race-walking distance.
Pacing a 20K
Run it even, or slightly negative. Bank time early and the last 5 km usually costs more than it gave. The 10K mark is halfway: at 1:40:00 even that is 50:00, and on a 3% negative split it is 51:30 with the back half at 4:51/km. Use the 5K and 15K marks as checkpoints, and judge the race from 15K on.
How it works
Arithmetic, not physiology. Distance is locked at 20.000 km (12.42742 mi). Pace = time / distance. This is even 20K race pace, not race-equivalence. For a 10K→20K or 20K→half estimate, use the race time predictor (Riegel). This page does not clone VDOT or McMillan tables.
- pace = time / 20.000 km
- 20K = 20.000 km = 12.427423845 mi
- half at this pace = pace × 21.0975 km
- 1 mile = 1.609344 km
Same even-pace math as the 10K pace calculator · 15K pace · 10 mile pace · half marathon pace · marathon pace · split calculator · pace calculator · race pace band.
Pacing aid only. Not a training plan. Not medical advice.
FAQ
What pace for a 1:40 20K?
A 1:40:00 20K is 8:03 per mile, or 5:00 per kilometer, at even pace. That is the same even-pace band as a 50:00 10K and a 1:15:00 15K. Distance is locked at 20.000 km (12.43 mi). There is no Calculate button; pace updates live.
How many miles is a 20K?
A 20K is 20.000 kilometers, which is 12.43 miles (12.427423845 mi using 1 mile = 1.609344 km). It is 1.0975 km (about 0.68 mi) shorter than a half marathon.
What is the halfway split for a 20K?
Halfway is the 10K mark. At 1:40:00 even pace you pass 10K in 50:00. On a slight 3% negative split you pass 10K in 51:30 (5:09/km), then close at 4:51/km and still finish in 1:40:00.
What half marathon time is the same pace as my 20K?
Holding a 1:40:00 20K pace (5:00/km) for the full 21.0975 km gives a 1:45:29 half marathon. That is the same pace stretched over 1.0975 km more, not a prediction. Fatigue usually adds time, so use the race time predictor (Riegel) for an estimate.
Is a 20K a good half marathon tune-up?
Many runners use a 20K as a long tempo or a dress rehearsal a few weeks before a half: it is close to the full distance, so it tests goal pace, shoes, and fueling without the full race load. This page only does the pace math; it is not a training plan.
Should I run a 20K at even pace or negative split?
Even pace or a slight negative split is the usual advice for road distances this long. Going out a few seconds per km too fast costs more late in the race than it saves early. Toggle Even / Negative to see both clocks for the same finish time.
Does this predict a 20K from a 10K?
No. This page is even-pace arithmetic for 20.000 km. It does not estimate a 20K from a shorter race, and it is not VDOT or McMillan. For a fatigue-based estimate from a recent race, use the race time predictor (Riegel).