How it works
required pace = goal time ÷ 26.2188 mi (or ÷ 42.195 km)
Divide the goal time by the distance and you have the required pace — nothing more exotic than that. What makes the marathon version useful is the fixed distance: World Athletics defines the race as exactly 42,195 m, which is 26 miles 385 yards, so the calculator never asks for a distance and both unit views describe the same physical speed. Under the hood the math runs in meters and seconds and only becomes miles or kilometers at display time, so the per-mile and per-km figures can never drift apart through rounding. Treat the even-pace answer as a ceiling rather than a plan: carbohydrate stores start emptying after roughly 30 km of racing, and a start just a few seconds per mile too aggressive is what buys you the wall over the closing 10 km.
Sources
- Marathon distance — World Athletics standard World Athletics (formerly IAAF) — the marathon is defined as exactly 42.195 km (26 miles 385 yards).
- Definition of average pace Average speed = distance ÷ time (kinematics); pace is its inverse, expressed as time per unit distance. Halliday, Resnick & Krane, "Physics", 4th ed., §2-2.
- Why even pace is the physiological optimum Riegel, P. S. (1981). "Athletic Records and Human Endurance." American Scientist 69(3), 285–290. Even-pace or slight negative-split strategies minimise energy cost over long events.
FAQ
What pace is a 4-hour marathon?
Breaking 4:00:00 takes an average of 9:09 per mile, or 5:41 per kilometer, with an even-pace halfway split of 1:59:59. Set the goal-time field to 4:00:00 and the calculator lays those numbers out alongside the matching speed.
What inputs matter most?
There are only two: your goal finish time and the unit you want pace displayed in. The honest part is choosing a goal that matches your training — a 3:30:00 target, for example, commits you to 8:01 per mile (4:59 per km) and a 1:45:00 half, so gut-check that against your recent long runs and tune-up races.
How should I read the result?
As the arithmetic floor of your goal, not a race plan. A sub-3 attempt demands 6:52 per mile (4:16 per km) and a 1:30:00 halfway crossing on paper — but most well-executed marathons start a touch conservative and earn the time back late, so build your plan around the pace with a cushion, not exactly on it.
Does this work in miles and kilometers?
Yes — a segmented toggle switches the display, and both views come from one internal number. The distinction matters on race day: 9:09 per mile and 5:41 per km describe the same 4:00 marathon, and misreading which one your watch shows against kilometer course markers can cost minutes over 26.2 miles.
Why might my real marathon differ from the even-pace math?
Because 42.195 km punishes every variable the division ignores: hills, headwind, heat, crowded early miles, missed bottles, and the fatigue curve of the final hour. Many runners plan the first half 1–2% easier than goal pace and keep 30–90 seconds of cushion at halfway instead of racing the exact even-pace figures.
What is the per-400 m figure for?
That is your goal-pace lap time on a standard track. Marathon pace feels deceptively gentle on fresh legs, so coaches prescribe long goal-pace blocks — often 6 to 16 km inside a long run — and the lap figure lets you check the effort every 400 m while you rehearse holding it tired.
Can beginners set a marathon goal this way?
Yes, but work in reverse: rather than picking a time and forcing the pace, race a half marathon or a long tune-up, see what pace you genuinely held, and let that suggest the goal. First-timers usually do better choosing to finish strong over chasing a round number.
The pace, speed, and split figures here are exact arithmetic on whatever goal you type in — the marathon you actually run still depends on training, course, weather, and fueling. Treat the even-pace numbers as planning targets, not a personalized prediction, race strategy, or medical guidance.