To train for a half marathon, run four to five times a week for 10 to 14 weeks: a long run that builds to about 18 to 20 km, one threshold session, and two to three easy runs. Keep roughly 80 percent of your running easy. The half is won on aerobic base and a long run developed patiently, not on race-pace heroics in training.
How long does it take to train for a half marathon?
If you can comfortably run 8 to 10 km, plan on 10 to 14 weeks. If you are starting from less, build a base to that point first, then begin the block. The half rewards endurance, and endurance is built through weeks of consistent aerobic running. There is no shortcut that does not arrive with an injury.
How many days a week should you run for a half marathon?
Four to five days a week suits most runners. The long run and the easy volume around it do the heavy lifting; one threshold session adds sharpness.
- First half marathon: 4 days, long run plus three easy runs, finish-focused.
- Improver: 4 to 5 days, one threshold session, a building long run, the rest easy.
- Time goal: 5 days, with some long runs finishing at goal half pace near the race.
What should a half marathon training week look like?
The week is anchored by the long run, supported by easy volume, and sharpened by one threshold session. The long run is the single biggest driver of half marathon fitness, so everything else is arranged to let you run it well.
| Day | Session |
|---|---|
| Monday | Rest or easy walk |
| Tuesday | Easy run, 40-50 min, plus a few strides |
| Wednesday | Quality: threshold intervals or tempo run |
| Thursday | Easy run, 30-40 min |
| Friday | Rest |
| Saturday | Long run, easy, building to 18-20 km |
| Sunday | Easy run or rest |
A sample improver week. Paces should come from your own numbers, not a generic chart.
How long should your longest run be?
Build the long run to about 18 to 20 km, two to three weeks before race day, then taper. You do not need to cover the full 21.1 km in training. Reaching 18 to 20 km at an easy effort builds the durability and aerobic strength that carry you through the final kilometers on race day.
Run the long run easy, at a conversational Zone 2 effort. The long run guide explains how to progress it safely and why easy is the point.
The mistake most half marathon runners make
Running the long run too fast, and the easy days too hard. When every run drifts into the grey zone, the long run stops building you and starts breaking you down, and the easy days never let you recover. The result is a plateau, or an injury, four weeks out.
The long run is built, not raced. Easy long runs develop the engine and the durability. Save the hard running for the one threshold session a week, and arrive at the start line fresh.
Finding your paces
Your easy, long, and threshold paces should come from your own heart rate, not a finish-time table. Work out your zones with the free heart rate zone calculator, or read how the five zones fit together in the heart rate zones guide.
How Run Mastery builds your half marathon plan
Run Mastery turns this into a plan built around you. You answer a few questions, and it estimates your VO2max and training zones, then builds a week shaped by your goal, level, and available days, with the long run progressed sensibly toward race day. As you train, the coach adapts to what you actually do. See the approach on the coaching page, or build your runner profile below and see your first week free.
