100 Mile Pace Calculator
14:24/mi
4.17mph
100 mi · 160.93 km
Right on the 24-hour line: 14:24/mi average, stops included.
- First 50 mi
- 14:24/mi
- Last 50 mi
- 14:24/mi
- Halfway
- 12:00:00
Same average pace from the first mile to the finish, stops included.
Checkpoints
25 mi
25.00 mi
Marathon
26.22 mi
50K
31.07 mi
Halfway · 50 mi
50.00 mi
100K
62.14 mi
75 mi
75.00 mi
Finish
100.00 mi
5 mile splits
5 mi
8.05 km
10 mi
16.09 km
15 mi
24.14 km
20 mi
32.19 km
25 mi
40.23 km
30 mi
48.28 km
35 mi
56.33 km
40 mi
64.37 km
45 mi
72.42 km
50 mi
80.47 km
55 mi
88.51 km
60 mi
96.56 km
65 mi
104.61 km
70 mi
112.65 km
75 mi
120.70 km
80 mi
128.75 km
85 mi
136.79 km
90 mi
144.84 km
95 mi
152.89 km
100 mi
Finish
10 km splits
10 km
6.21 mi
20 km
12.43 mi
30 km
18.64 mi
40 km
24.85 mi
50 km
31.07 mi
60 km
37.28 mi
70 km
43.50 mi
80 km
49.71 mi
90 km
55.92 mi
100 km
62.14 mi
110 km
68.35 mi
120 km
74.56 mi
130 km
80.78 mi
140 km
86.99 mi
150 km
93.21 mi
160 km
99.42 mi
160.93 km
Finish
Even pace for 100 miles, not a race-equivalence predictor. Pacing aid only — not a training plan or medical advice. 50 mile pace · 50K pace · 100K pace · marathon pace · race fueling · grade-adjusted pace · race time predictor · pace card.
Worked examples
24:00:00 100 mile
14:24 /mi · 8:57 /km · 5 mi every 1:12:00
20:00:00 100 mile
12:00 /mi · 7:27 /km
28:00:00 100 mile
16:48 /mi · 10:26 /km
30:00:00 100 mile
18:00 /mi · 11:11 /km
32:00:00 100 mile
19:12 /mi · 11:56 /km
36:00:00 100 mile
21:36 /mi · 13:25 /km
How it works
Arithmetic, not physiology. Distance is locked at 100 miles (160.93 km). Pace = time / distance, and the time includes every aid-station stop, so it is your average pace, not your moving pace. This is even 100 mile pace, not race-equivalence. The sub-24 line compares your goal with 24:00:00, which is 14:24/mi. Fade runs the first 50 miles 3% faster and the last 50 miles 3% slower. Run-walk solves for the running pace that keeps the same average when every 5 minutes holds 3:00 of running and 2:00 of walking at 20:00/mi, so every split clock is unchanged. For a 50 mile→100 mile 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 mi
- 100 mi = 160.9344 km
- sub-24 = 24:00:00 / 100 mi = 14:24 /mi
- run pace = 3:00 / (5:00 / pace − 2:00 / walk pace)
Same even-pace math as the 50 mile pace calculator · 50K pace · 100K 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 24-hour 100 mile?
A 24:00:00 100 mile is 14:24 per mile, or 8:57 per kilometer, at even pace (4.17 mph · 6.71 km/h). Halfway (50 mi) comes at 12:00:00, the 100K mark at 14:54:46, and every 5 miles ticks by on a 1:12:00 clock. Distance is locked at 100 miles (160.93 km). There is no Calculate button; pace updates live.
What pace do I need for a sub-24 hour 100 mile?
Faster than 14:24 per mile (8:57 per km) on average, with every aid-station stop, shoe change, and walk counted in that average. Many 100 mile races give a separate buckle or award for finishing under 24 hours, but the rules differ by race, so check yours. SplitLab shows how far under or over 24 hours your goal is, right under the giant number.
How many kilometers is 100 miles?
100 miles is 160.9344 kilometers (1 mile = 1.609344 km). That is twice a 50 mile and about 60.9 km (37.9 miles) past a 100K. Trail 100s are often a few miles long or short, 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 100 miles, stops included, because that is what the clock measures. If you plan to spend 2 hours total at aid stations in a 24-hour race, your moving time is 22:00:00, so you need about 13:12 per mile (8:12 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 100 mile?
Most runners slow down over the second half of a 100, through the night and on tired legs, so a perfectly even plan is rare. Pick Fade to run the first 50 miles 3% faster and the last 50 miles 3% slower with the same finish: for 24:00:00 that is 13:58/mi out and 14:50/mi back, with halfway at 11:38:24. It is a planning shape, not a prediction of how much you will slow.
Should I run-walk a 100 mile?
Almost every 100 mile finisher walks a lot of it, and many plan it from the start. With Run-walk selected, SplitLab shows the running pace that keeps your goal average: for a 24:00:00 100 mile, running 3:00 and walking 2:00 at a 20:00/mi hike means running about 12:08/mi (7:32/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 50 mile time translate to a 100 mile?
Riegel's formula (T2 = T1 × (D2/D1)^1.06) turns a 10:00 50 mile into a 20:50:58 100 mile and an 11:00 50 mile into 22:56:03. That is a best case, and at this distance it is usually very optimistic: night running, sleep loss, aid stops, weather, and terrain add a lot of 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 100 mile?
At 60 g of carbs per hour, a 24:00:00 100 mile is about 1,440 g, or 58 gels of 25 g. That is the fueling calculator's Auto setting for races of 2.5 hours and longer. Over a full day 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.