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Race preparation · 6 min read

Your first half marathon

Twelve to sixteen weeks of consistent running, with a long run built to about 18 km (11 mi), is the standard path to a first half marathon.

The short answer

Most runners need 12 to 16 weeks to prepare for a half marathon, starting from a base of about 20 to 25 km (12 to 15 mi) per week. The key session is the weekly long run, built gradually to roughly 18 km (11 mi).

You do not need to run the full race distance in training. Time on feet, consistency and a sensible taper matter more than one heroic long run.

The weekly pattern

Four or five runs per week works well: several easy runs, one faster session (tempo or intervals), and the long run. Keep 70 to 80 percent of the week easy.

Rest days are part of the plan, not a failure of commitment. If you are new to the distance, err on the side of more easy days.

Easy runs
Conversational pace; the bulk of the week.
Tempo run
20–40 minutes at comfortably hard effort.
Long run
Build toward 18 km, mostly easy.

Pacing the race

The half marathon rewards patience. Runners who go out 10 seconds per kilometre too fast usually fade hard in the last 5 km. Start at a pace you could hold for 25 km and let the last third come to you.

A useful estimate: your half-marathon pace is usually close to 10K pace plus 10 to 15 seconds per kilometre, or 5K pace plus 25 to 35 seconds. Use our pace calculator to see equivalent times, then treat them as estimates rather than promises.

Respect the distance. The first 10 km should feel almost easy; the race starts at 15 km.

Fueling and shoes

Practise taking water and 30 to 60 grams of carbohydrate per hour on long runs. Race day should be a repeat of a routine you have already tested, not a first experiment.

Shoe-wise, most runners use a cushioned daily or long-run trainer, and step into a faster shoe for race day if they have one. Carbon shoes can help over 21 km, but a well-fitted trainer you have trained in is a perfectly good first-race choice.

Half-marathon rotations

Last reviewed Sep 30, 2026 · BuildMyRotation editorial team

General education, not medical advice. See a qualified professional for persistent pain.