Training plans Half marathon
The sub-1:25 half marathon
A sub-1:25 half marathon works out at 4:02/km (6:29/mi), held for the full distance. Typical preparation is 12–16 weeks of 56–76km a week, spread over 5–6 sessions. The work splits into three paces: easy volume at 4:57–5:32/km, threshold running near 3:57/km, and interval reps around 3:42/km. A recent race time is the truest guide to whether this goal fits this season.
Last updated 2026-07-03 · paces computed, not copywritten
Goal pace
4:02/km
6:29/mi
Typical build
12–16 weeks
56–76 km/week
Runs per week
5–6
3 key sessions + easy volume
Required paces
| SESSION | PACE (/KM) |
|---|---|
| Easy runs | 4:57–5:32 |
| Long run | 4:27–4:57 |
| Tempo | 3:57 |
| Intervals | 3:42 |
| Race pace | 4:02 |
Splits at goal pace
| CHECKPOINT | CLOCK |
|---|---|
| 5K | 20:09 |
| 10K | 40:17 |
| 15K | 1:00:26 |
| Finish | 1:25:00 |
These are dead-even splits — going out quicker than 4:02/km is the most common way a 1:25 slips away in the final quarter.
A typical week
Key session 1
Intervals — reps around 3:42/km (5K effort) with jog recoveries
Key session 2
Tempo — sustained comfortably-hard running near 3:57/km
Long run
The week's cornerstone at 4:27–4:57/km, adding 1:25-pace finishes as race day nears
Plus 3+ easy runs. The remaining runs stay genuinely easy (4:57–5:32/km); they carry the volume the key sessions are built on.
Asked often
- What pace is a sub-1:25 half marathon?
- 4:02 per kilometre, held for the full half marathon. Even or slightly negative splits protect a 1:25 far better than a fast start.
- How long should I train for a sub-1:25 half marathon?
- From a reasonable base, 12–16 weeks. Start from where your running actually is: a recent race time sets the half marathon timeline better than the calendar does.
- What happens if I miss training weeks?
- A static plan quietly breaks — every later week assumes fitness you didn't build. An adaptive plan like RunV's re-ramps volume and recalibrates paces so the 1:25 goal stays honest.
This fitness at other distances
- Marathon: 2:57:13 equivalent
- 10K: 38:31 equivalent
- 5K: 18:29 equivalent
The engine behind your sub-1:25
RunV builds your sub-1:25 plan around your week, then recalibrates it after every run — finished, cut short, or missed.
