Half marathon training load
How much should you run each week for a half? Put in where you are, how many weeks you have and the peak you want, and see the whole block.
Your details
Peak week
40.0 km
reached safely, then a 2 week taper
- Week 122.0 km
- Week 224.2 km
- Week 326.6 km
- Week 421.3 km
- Week 529.3 km
- Week 632.2 km
- Week 735.4 km
- Week 828.3 km
- Week 939.0 km
- Week 1040.0 km
- Week 11 (taper)30.0 km
- Week 12 (taper)20.0 km
- Longest run (40% of peak, capped at 19 km)16.0 km
Grow the week gently and keep most runs easy. The taper cuts distance but keeps a little pace, so you arrive fresh rather than flat.
Persistent pain, low mood, poor sleep or periods stopping during heavy training are signs to ease off and talk to your GP.
The working
20 km to a 40 km peak
Growing 10% a week with every fourth week at 80%: 22, 24.2, 26.6, 21.3, 29.3, 32.2, 35.4, 28.3, 39 and 40 km in week 10. Then the taper: 30 km and 20 km. The longest run is about 40% of the peak, 16 km here, capped at 19 km.
Typical peaks
Rough guide
| Goal | Peak week |
|---|---|
| To finish | 25 to 35 km |
| Under 2 hours | 35 to 50 km |
| Under 1:45 | 45 to 60 km |
The taper
Why two weeks
A meta-analysis of tapering (Bosquet 2007) found cutting volume by 40 to 60% over about two weeks, while keeping some pace, gave the best race results. You will feel twitchy. That is normal.
Read with care
What this cannot tell you
- IntensityKeep most of the week easy; this is distance only.
- Injury historyBuild more slowly if you get injured easily.
- HealthMissed periods, low mood or poor sleep: ease off and see your GP.
Questions
Common questions
How many miles a week for a half marathon?
Many runners peak around 20 to 30 miles (30 to 50 km).
How long should I taper for a half?
About 1 to 2 weeks.
What is the longest run before a half?
Usually 10 to 12 miles (16 to 19 km).
Sources
- Bosquet L, Mujika I et al. Effects of tapering on performance: a meta-analysis. Med Sci Sports Exerc 2007
- Nielsen RO et al. Excessive progression in weekly running distance and risk of running related injuries. J Orthop Sports Phys Ther 2014
- Gabbett TJ. The training injury prevention paradox. Br J Sports Med 2016
Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.
Before you push on
New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.
Related
Related calculators
- Marathon training load calculatorWeekly marathon distance with a three week taper.Open
- Half marathon pace calculatorThe steady pace for your half marathon goal.Open
- Long run build up calculatorWeek by week long runs up to your target.Open
- Training days to race calculatorDays, runs and long run Sundays before your race.Open
- Running load checkerThis week against your usual, as a simple ratio.Open
- Running fuel calculatorGrams of carbs an hour, and how many gels.Open