100K Pace Calculator
11:35/mi
5.18mph
100.00 km · 62.14 mi
- First 50K
- 11:35/mi
- Last 50K
- 11:35/mi
- Halfway
- 6:00:00
Same average pace from the first kilometer to the finish, stops included.
Checkpoints
Marathon
26.22 mi
Halfway · 50K
31.07 mi
40 mi
40.00 mi
50 mi
50.00 mi
Finish
62.14 mi
Mile splits
1 mi
1.61 km
2 mi
3.22 km
3 mi
4.83 km
4 mi
6.44 km
5 mi
8.05 km
6 mi
9.66 km
7 mi
11.27 km
8 mi
12.87 km
9 mi
14.48 km
10 mi
16.09 km
11 mi
17.70 km
12 mi
19.31 km
13 mi
20.92 km
14 mi
22.53 km
15 mi
24.14 km
16 mi
25.75 km
17 mi
27.36 km
18 mi
28.97 km
19 mi
30.58 km
20 mi
32.19 km
21 mi
33.80 km
22 mi
35.41 km
23 mi
37.01 km
24 mi
38.62 km
25 mi
40.23 km
26 mi
41.84 km
27 mi
43.45 km
28 mi
45.06 km
29 mi
46.67 km
30 mi
48.28 km
31 mi
49.89 km
32 mi
51.50 km
33 mi
53.11 km
34 mi
54.72 km
35 mi
56.33 km
36 mi
57.94 km
37 mi
59.55 km
38 mi
61.16 km
39 mi
62.76 km
40 mi
64.37 km
41 mi
65.98 km
42 mi
67.59 km
43 mi
69.20 km
44 mi
70.81 km
45 mi
72.42 km
46 mi
74.03 km
47 mi
75.64 km
48 mi
77.25 km
49 mi
78.86 km
50 mi
80.47 km
51 mi
82.08 km
52 mi
83.69 km
53 mi
85.30 km
54 mi
86.90 km
55 mi
88.51 km
56 mi
90.12 km
57 mi
91.73 km
58 mi
93.34 km
59 mi
94.95 km
60 mi
96.56 km
61 mi
98.17 km
62 mi
99.78 km
62.14 mi
Finish
5 km splits
5 km
3.11 mi
10 km
6.21 mi
15 km
9.32 mi
20 km
12.43 mi
25 km
15.53 mi
30 km
18.64 mi
35 km
21.75 mi
40 km
24.85 mi
45 km
27.96 mi
50 km
31.07 mi
55 km
34.18 mi
60 km
37.28 mi
65 km
40.39 mi
70 km
43.50 mi
75 km
46.60 mi
80 km
49.71 mi
85 km
52.82 mi
90 km
55.92 mi
95 km
59.03 mi
100 km
62.14 mi
Even pace for 100.000 km, not a race-equivalence predictor. Pacing aid only — not a training plan or medical advice. 50K pace · 50 mile pace · 100 mile pace · marathon pace · race fueling · grade-adjusted pace · race time predictor · pace card.
Worked examples
12:00:00 100K
11:35 /mi · 7:12 /km · 5 km every 36:00
8:00:00 100K
7:43 /mi · 4:48 /km
10:00:00 100K
9:39 /mi · 6:00 /km
11:00:00 100K
10:37 /mi · 6:36 /km
14:00:00 100K
13:31 /mi · 8:24 /km
How it works
Arithmetic, not physiology. Distance is locked at 100.000 km (62.14 mi). Pace = time / distance, and the time includes every aid-station stop, so it is your average pace, not your moving pace. This is even 100K pace, not race-equivalence. Fade runs the first 50K 3% faster and the last 50K 3% slower. Run-walk solves for the running pace that keeps the same average when every 5 minutes holds 4:00 of running and 1:00 of walking at 16:00/mi, so every split clock is unchanged. For a 50K→100K estimate, use the race time predictor (Riegel), and expect it to be optimistic. This page does not clone VDOT or McMillan tables.
- pace = time / 100.000 km
- 100K = 100.000 km = 62.1371 mi
- run pace = 4:00 / (5:00 / pace − 1:00 / walk pace)
Same even-pace math as the 50K pace calculator · 50 mile pace · 100 mile pace · marathon pace · split calculator. Plan gels on the fueling calculator; adjust for hills with grade-adjusted pace and for hot days with heat pace.
Pacing aid only. Not a training plan. Not medical advice.
FAQ
What pace is a 12-hour 100K?
A 12:00:00 100K is 11:35 per mile, or 7:12 per kilometer, at even pace (5.18 mph · 8.33 km/h). Halfway (50K) comes at 6:00:00, every 5 km ticks by on a 36:00 clock, and the 50 mile mark is at 9:39:22. Distance is locked at 100.000 km (62.14 mi). There is no Calculate button; pace updates live.
How many miles is a 100K?
A 100K is 100.000 kilometers, which is 62.1371 international miles (1 mile = 1.609344 km). That is twice a 50K and about 12.1 miles (19.5 km) short of a 50 mile. Trail 100Ks are often a little long or short of 100.000 km, so check the course's own distance before you print splits.
Does the pace include aid-station stops?
Yes. The pace here is your average over the whole 100K, stops included, because that is what the clock measures. If you plan to spend 1 hour total at aid stations in a 12-hour race, your moving time is 11:00:00, so you need about 10:37 per mile (6:36 per km) while moving. Type the moving time into the box to see that pace and its splits.
Should I plan for a fade in a 100K?
Most runners slow down over the second half of a 100K, so a perfectly even plan is rare. Pick Fade to run the first 50K 3% faster and the last 50K 3% slower with the same finish: for 12:00:00 that is 11:14/mi out and 11:56/mi back, with halfway at 5:49:12. It is a planning shape, not a prediction of how much you will slow.
Should I run-walk a 100K?
Many 100K finishers do, especially on trail. With Run-walk selected, SplitLab shows the running pace that keeps your goal average: for a 12:00:00 100K, running 4:00 and walking 1:00 at a 16:00/mi hike means running about 10:50/mi (6:44/km). Your clocks at every checkpoint stay the same as even pace. On trail courses, power-hiking the climbs is the most common walk break.
How does my 50K time translate to a 100K?
Riegel's formula (T2 = T1 × (D2/D1)^1.06) turns a 5:00 50K into a 10:25:29 100K and a 5:30 50K into 11:28:02. That is a best case, and at this distance it is usually optimistic: night running, aid stops, weather, and terrain add time. This page does not use VDOT or McMillan tables. Try other races on the race time predictor.
How many gels do I need for a 100K?
At 60 g of carbs per hour, a 12:00:00 100K is about 720 g, or 29 gels of 25 g. That is the fueling calculator's Auto setting for races of 2.5 hours and longer. Over a long ultra almost nobody lives on gels alone; most runners mix in real food and drink mix from aid stations. Practice your plan in long training runs. This is not medical advice.