Sub-40 5k
A sub-40 5k means holding 12:52 per mile (8:00 per km) the whole way — no fade. Here’s the pace broken down, and the honest question of whether it’s your race yet.
Even splits for sub-40
| 1K | 8:00 |
| 2K | 16:00 |
| 3K | 24:00 |
| 4K | 32:00 |
| 5K · finish | 40:00 |
The pace for a sub-40 5k
You need 12:52 per mile, or 8:00 per km, and you need it evenly — the splits above are the plan, not the average. Go out faster and the last quarter takes it all back with interest. See what that pace does everywhere else on the 12:52 /mile pace page, or the 8:00 /km page. The pace calculator handles any goal you like.
What sub-40 means at other distances
Using Riegel’s equivalence, a sub-40 5k projects to roughly these times elsewhere — assuming the endurance to back them up.
| Distance | Equivalent | Pace /mi |
|---|---|---|
| Mile | 12:02 | 12:02 |
| 10K | 1:23:24 | 13:25 |
| Half marathon | 3:04:00 | 14:02 |
| Marathon | 6:23:39 | 14:38 |
Is a sub-40 5k realistic?
The pace is the easy part to know and the hard part to earn. A time goal is only realistic if your training has built the engine for it — the long runs, the weeks on your feet, the easy miles that make the fast ones possible. Chasing the number without the base is how plans fall apart around week three.
That’s the gap Liftrun is built to close: it works backward from your goal, then adapts the plan every morning from your sleep, heart rate, and the runs already in your legs — so the pace above becomes a target you’ve actually trained for, not just done the maths on.