What pace do I need for a sub-4:00 marathon?

About 5:41 per km, or 9:09 per mile. That's 4:00:00 (14,400 seconds) divided by the standard marathon distance of 42.195 km, which works out to 341.4 seconds per km — 5 minutes 41 seconds, rounded.

How is marathon pace calculated from a goal time?

Divide your total goal time in seconds by the race distance: pace (seconds per km) = goal time (seconds) ÷ 42.195. For miles, divide by 26.2188 (the marathon distance in miles) instead, or convert the per-km pace using the exact factor 1.609344 km per mile.

Why is the marathon distance 42.195 km and not 42.2?

42.195 km is the standard set by World Athletics, based on the 1908 London Olympics course distance (26 miles 385 yards) converted and fixed as the official distance in 1921. The commonly rounded '42.2 km' you see on medals is a rounding of that, not the defined value.

Does my goal pace need to include water stops?

No — a pace calculated from goal time and distance is your required average pace for the full distance, not accounting for individual stops. Runners typically bank a little time on faster segments to cover a few seconds lost at aid stations, rather than building stop time into the pace target itself.

Guide

Marathon pace calculator: work backward from goal time

A goal finish time only becomes useful on race day once it's a pace per km or mile you can check against your watch.

By Buğra SözeriPublished September 25, 2026

“I want to run a sub-4:00 marathon” is a goal. “5:41 per km” is something you can actually check against your watch at mile 3. Converting a goal finish time into a required pace is simple division, but the rounding matters more than it looks — the difference between 5:40 and 5:42 per km compounds to over 50 seconds across 42.195 km.

The formula: goal time ÷ distance

Pace in seconds per km equals your total goal time in seconds divided by the race distance in km. The standard marathon distance is 42.195 km (26.2188 miles), fixed by World Athletics since 1921.

Goal finish time	Pace per km	Pace per mile
3:00:00	4:16 /km	6:52 /mi
3:30:00	4:59 /km	8:01 /mi
4:00:00	5:41 /km	9:09 /mi
4:30:00	6:24 /km	10:18 /mi
5:00:00	7:07 /km	11:27 /mi

Worked example for the 4:00:00 row: 4 hours = 14,400 seconds. 14,400 ÷ 42.195 ≈ 341.4 seconds per km, which is 5 minutes 41.4 seconds — rounds to 5:41/km. Converting to per-mile pace multiplies by the exact factor 1.609344 (NIST SP 811): 341.4 × 1.609344 ≈ 549.4 seconds, or 9:09/mi.

Why 5-second rounding matters over 42.195 km

A pace that's off by just 5 seconds per km — 5:41 vs. 5:46 — adds up to 3 minutes 30 seconds over the full marathon distance (5 seconds × 42.195 ≈ 211 seconds). That's the gap between finishing at 4:00:00 and 4:03:30, which is exactly the kind of drift that comes from eyeballing pace instead of calculating it precisely. If your goal time has a hard cutoff (a qualifying standard, for instance), calculating the exact pace rather than a rounded one is worth the extra 10 seconds of math.

Adjusting for half-marathon or other distances

The same division works for any race distance — a half marathon is 21.0975 km, a 10K is 10 km, a 5K is 5 km. Swap the divisor and the same goal-time-to-pace math applies. If you already know your pace from a recent race and want to see what finish time it would produce at a different distance, that's the reverse calculation — see converting your running pace from miles to km for the unit-conversion side of pace math, or the pace calculator for either direction.

Frequently asked questions

What pace do I need for a sub-4:00 marathon?: About 5:41 per km, or 9:09 per mile. That's 4:00:00 (14,400 seconds) divided by the standard marathon distance of 42.195 km, which works out to 341.4 seconds per km — 5 minutes 41 seconds, rounded.
How is marathon pace calculated from a goal time?: Divide your total goal time in seconds by the race distance: pace (seconds per km) = goal time (seconds) ÷ 42.195. For miles, divide by 26.2188 (the marathon distance in miles) instead, or convert the per-km pace using the exact factor 1.609344 km per mile.
Why is the marathon distance 42.195 km and not 42.2?: 42.195 km is the standard set by World Athletics, based on the 1908 London Olympics course distance (26 miles 385 yards) converted and fixed as the official distance in 1921. The commonly rounded '42.2 km' you see on medals is a rounding of that, not the defined value.
Does my goal pace need to include water stops?: No — a pace calculated from goal time and distance is your required average pace for the full distance, not accounting for individual stops. Runners typically bank a little time on faster segments to cover a few seconds lost at aid stations, rather than building stop time into the pace target itself.

Sources & references

Authoritative references cited by this piece. Verified by Buğra Sözeri on the dates shown and re-checked at every deploy.

NIST SP 811 — Guide for the Use of the International System of Units — Source for the exact mile-to-kilometer conversion factor (1.609344) used in pace conversions(as of 2026-09-25)
World Athletics — Competition Rules, Book C2.1 — Defines the standard marathon distance (42.195 km) that pace targets are built from(as of 2026-09-25)