Marathon Pace Calculator
9:09/mi
2:00:00half
- First half
- 9:09/mi
- Second half
- 9:09/mi
- Half split
- 2:00:00
Kilometer checkpoints
5K
5.00 km
10K
10.00 km
15K
15.00 km
20K
20.00 km
Half
21.10 km
25K
25.00 km
30K
30.00 km
35K
35.00 km
40K
40.00 km
Finish
42.20 km
Mile checkpoints
5 mi
5.00 mi
10 mi
10.00 mi
13.1 mi
13.10 mi
Half
13.11 mi
15 mi
15.00 mi
20 mi
20.00 mi
26.2 mi
26.20 mi
Finish
26.22 mi
Arithmetic for 26.2, not a 5K→marathon predictor. Pace calculator · Race time predictor · Race pace band · Pace card · 50K pace · 50 mile pace · 100 mile pace · 100K pace.
Worked example
4:00:00 marathon
9:09 /mi · 5:41 /km · even half 2:00:00 · negative half 2:03:36
Formulas
Same arithmetic as the running pace calculator. Negative split: first half even × 1.03, second half even × 0.97. Finish time matches the goal. Not a 5K→marathon predictor — that is the race time predictor (Riegel).
- pace = time / 42.195 km
- 1 mile = 1.609344 km · marathon = 42.195 km
Print mile, km, or 400m marks for any distance on the split calculator · race pace band. Boston qualifying standards live on the Boston qualifier calculator.
FAQ
What pace is a 4-hour marathon?
A 4:00:00 marathon is 9:09 per mile, or 5:41 per kilometer, at even pace. That is the World Athletics distance of 42.195 km (26.2188 mi). Load the 4:00 chip on this page to see half split and checkpoints.
What pace is a 3:30 marathon?
A 3:30:00 marathon is 8:01 per mile, or 4:59 per kilometer, at even pace. The 3:30 chip fills the goal time and computes splits live.
How do I negative-split a marathon?
Run the first half about 3% slower than even pace and the second half about 3% faster. Finish time still matches the goal. A 4:00:00 plan hits halfway in 2:03:36 instead of 2:00:00, then closes in 1:56:24. This is a pacing strategy, not a fitness model.
Is this a race predictor from a 5K?
No. This page is arithmetic for 26.2 miles. It does not estimate a marathon from a 5K or 10K. For that fatigue-based estimate, use the race time predictor (Riegel).
Mile vs km checkpoints — which should I use?
Use the unit your course marks. Many road marathons show both kilometer clocks and mile markers. This table lists 5K through 40K plus half and finish, and mile marks at 5, 10, 13.1, 15, 20, and 26.2. 13.1 mi and the official half (21.0975 km) are a few meters apart, so both appear.
Why 42.195 km?
That is the World Athletics marathon distance. In international miles it is 26.2188 mi, not a rounded 26.2. SplitLab uses 42.195 km and 1 mile = 1.609344 km so a 4-hour marathon is 9:09/mi, not a guess from 26.2 on the nose.
Does this tell me if I can qualify for Boston?
No. Boston qualifying standards are age- and gender-specific and change by year. This calculator only turns a goal time into even and negative-split paces. A dedicated qualifying-times page can come later — we will not invent those standards here.