Half marathon training
Free Half Marathon Training Plan
The half marathon is long enough that aerobic endurance decides it and short enough that pace still matters. A good plan grows your long run patiently, adds threshold and race-pace work, and gets you to the start line fresh.
- Typical build
- 10 to 16 weeks
- Runs per week
- 3 to 5, about 80 percent easy
- Long run peak
- 16 to 20 km, or about 2 hours
- Taper
- 10 to 14 days
How a half marathon plan is structured
A half marathon plan usually runs 10 to 16 weeks. The first third builds easy volume and the long run. The middle third adds a weekly threshold session and starts putting race-pace segments into some long runs. The last third is race-specific work and the taper. Weekly volume rises gradually, around 10 percent a week at most as a conservative guide, and every third or fourth week is lighter so the training can sink in.
Grow the long run patiently
The long run is the spine of the plan. Add about 1 to 2 kilometres a week, with a shorter long run every few weeks, until you reach 16 to 20 kilometres or roughly 2 hours, whichever comes first. You do not need to run the full distance before race day. First-timers should keep long runs fully easy; runners with a time goal can finish later long runs with 3 to 6 kilometres at goal pace.
Threshold and race-pace sessions
One quality session a week does most of the work. Early on, threshold intervals such as 3 × 10 minutes at comfortably hard effort with 2 minutes easy between. Later, race-pace work such as 3 × 3 km at goal half marathon pace with 3 minutes easy, or a continuous 8 to 10 km at goal pace inside a longer run. Half marathon pace should feel controlled but focused; if it feels hard in training it will not hold for 21 kilometres.
Practise fuelling and pacing
Races under about 90 minutes need little fuel, but most runners take longer. Practise taking 30 to 60 grams of carbohydrate per hour on long runs, using the gels or drinks you will race with, so race day holds no surprises for your stomach. Practise pace too: settle into goal pace by the second kilometre and treat the first 10 kilometres as patient work, not a chance to bank time.
Taper and race day
Over the last 10 to 14 days, cut volume by roughly 30 to 50 percent while keeping a little race-pace running so you stay sharp. The final long run of note comes about two weeks out. Expect to feel restless, even sluggish, during the taper; that is normal. On race day, aim for even splits, then use whatever is left over the last 5 kilometres.
A sample week
A mid-plan week for a runner on four to five days, about 40 to 50 km. Three-day runners keep the quality session, one easy run and the long run.
- Mon
- Rest
- Tue
- Threshold: 15 min easy, 3 × 10 min comfortably hard, 2 min easy between, 10 min easy
- Wed
- Easy run, 45 min
- Thu
- Easy run, 35 min with 6 strides
- Fri
- Rest
- Sat
- Easy run, 30 min, or cross-training
- Sun
- Long run, 16 km easy, last 4 km at goal half marathon pace
The mistake that ruins half marathon builds
Increasing the long run and the weekly mileage and the intensity all at once. Each is reasonable on its own; together they are how most half marathon injuries start. Change one thing at a time, keep easy runs easy, and take the lighter week even when you feel good.
Common questions
How long should I train for a half marathon?
Ten to sixteen weeks for most runners. If you are already running 25 km a week comfortably, 10 to 12 weeks is enough; newer runners benefit from the longer build.
Do I need to run 21 km before race day?
No. Long runs of 16 to 20 km, or about two hours, build the endurance you need. Race-day adrenaline and the taper carry you the rest of the way.
What pace is a sub-2 hour half marathon?
5:41 per kilometre, or 9:09 per mile. A realistic sub-2 runner can usually run 10K in about 55 to 56 minutes.
Is the half marathon plan really free?
Yes. AthleteSpace is free with no credit card, and you can build and see your plan before making an account.