Sub-3 hour Marathon Pace

Sub-3 is the most recognised amateur marathon barrier, and the reason it is hard is arithmetic as much as fitness. The pace it needs must be held for the whole distance, and there is no part of the race where you can afford to drift and make it back later. Everything below is generated from the exact distance of 42.195 km, so the numbers do not soften anywhere.

The most common way sub-3 is missed is by a small margin, not a large one. Runners arrive at 30 km on pace, lose a handful of seconds per kilometre over the closing stretch, and finish just the wrong side of three hours. The fade table on this page puts a number on that: it shows what the finish becomes if the second half is run two, five or ten percent slower than the first, which is a far more honest way to plan than assuming even pacing will simply happen.

If you are deciding whether this goal is realistic, the equivalent-times table is the sharper test. It projects the fitness this marathon implies onto shorter races. If your recent 10K or half is well outside those figures, the goal is ahead of the evidence rather than behind it.

Checkpoint times for a 3:00:00 marathon

The 30 km checkpoint is the one that decides a sub-3 attempt. Arrive there on the figure below and the goal is still yours to lose. Arrive a minute down and the arithmetic stops being friendly, because the pace required over what is left is faster than the pace that just proved too hard.

What a fade costs

Sub-3 is missed by seconds far more often than by minutes, which is exactly what this table is for. Read the two percent row first: that is the version that catches people who thought they were fine.

Every kilometre split for a 3:00:00 marathon

All 43 rows, ending on the final 195 metres so the last elapsed time is exactly 3:00:00 rather than close to it.

Every mile split for a 3:00:00 marathon

Many marathons mark both units. A mile marker arriving between two kilometre markers gives you an extra chance to check the plan without waiting for the next kilometre.

Equivalent race times

What a 3:00:00marathon implies at shorter distances, using Riegel's formula t2 = t1 x (d2 / d1) ^ 1.06. Projecting downwards like this is the more trustworthy direction, because marathon fitness generally implies you could run the shorter time. The methodology page sets out where the model stops being reliable.

Adjust the goal

If this is not quite your target, the neighbouring goals show what a step in either direction costs per kilometre, and the pace calculator will take any time you type in.

Frequently asked questions

Last reviewed 2026-08-05. Formulas, constants and sources: methodology. Changes to any calculation are logged in the changelog.