Set your half marathon goal time. Get the exact pace per km and mile, your 10 km split, a kilometre-by-kilometre race strategy, and Riegel-predicted finish times for every standard distance. How accurate is this?
Your Goal Time
Hours
Minutes
Seconds
Units
Quick Goals
Who Runs This
Your Half Marathon Pace
to finish a half marathon in 2:00:00
Per Mile
9:09
Speed
10.55
km/h
10 km Split
56:53
| Distance | Split | Cumulative | Pace |
|---|---|---|---|
| 5 km | 28:26 | 28:26 | 5:41 |
| 10 km | 28:26 | 56:53 | 5:41 |
| 15 km | 28:26 | 1:25:19 | 5:41 |
| 20 km | 28:26 | 1:53:45 | 5:41 |
| FINISH · 21.1 km | 6:15 | 2:00:00 | 5:41 |
How a 5:41/km half marathon maps to other race distances at the same relative effort.
Coach's note. A 2:00:00 half marathon predicts a 26:05 5K. If your 5K PR is faster than that, you have the leg speed — channel your training into aerobic endurance and long tempo runs.
Avg Pace
5:41
min/km
Avg Pace
9:09
min/mile
Speed
10.55
km/h
400 m Lap
2:17
track pace
Key kilometre targets for a controlled, progressive 2:00 half marathon.
The arc of a great half. Run 5 s/km conservative through km 3 to keep aerobic cost down. Hold even effort km 4–14. From km 15 the race truly begins — that is where your training investment pays out. Anyone can run the first 10 km fast; the fastest half marathoners run the last 7 km the hardest.
The 10 km mark is your truth meter
By 10 km you should feel controlled and breathing steadily. If you are already gasping, you started too fast, the next 11 km will be damage control. If you feel strong, stay disciplined: the temptation to surge here is a trap. Bank that energy for km 15 onward where it pays compound interest.
The dark zone: km 13–17
This is where half marathons fall apart. You are past the early excitement, not yet close enough to the finish to feel the pull. Glycogen starts to thin, legs complain, and pace drifts. This zone is won in training, specifically in long tempo runs where you hold effort through discomfort. Rehearse it mentally every long run. When the dark zone arrives on race day, you will have been there before.
Race-day nutrition is simpler than you think
Sub-90-minute runners rarely need gels, a solid breakfast and well-stocked glycogen stores are enough. From 90–150 minutes, one gel at km 8–10 prevents the late-race dip. Beyond 2:30, two gels spaced 40 min apart are your friend. The only rule that matters: practise this exact protocol on your long training runs. Your gut needs as much training as your legs.
Half marathon pace ≠ threshold pace
Your half marathon race pace sits at roughly 80–88 % of VO₂max, above pure threshold, below all-out 10K effort. It should feel "comfortably hard" from the gun: controlled but not conversational. Many runners train their threshold well but under-practise sustained half-marathon-specific effort. Long progression runs finishing at goal pace are the single best race-specific stimulus you can add.
Taper smart — do not stop
In the final 10 days, cut your volume by 30–40 % but keep your intensity. Most first-timers taper too aggressively and arrive at the start line feeling flat, slow, and nervous. Two or three short sessions at goal pace in the final week will keep your neuromuscular system sharp without accumulating fatigue. Trust the training, taper legs feel heavy because they are recovering, not because you are losing fitness.
Use your 10K time as a reality check
The Riegel formula suggests a half marathon takes roughly 2.09× your 10K time. If your goal half marathon is far faster than that implies, your training block will need to close the gap, not just your race-day courage. Conversely, a recent strong 10K PR is the single best predictor of half marathon potential. Race a 10K two to four weeks out and use this calculator to translate that result into your half marathon goal pace.