Running

12-Week Half Marathon Training Plan

Updated July 2026 · 9 min read

The half marathon rewards patience and volume. Twelve weeks gives you time to build a long run to 90 minutes, develop lactate threshold with tempo work, and arrive at the start line fresh. This plan targets runners who can already run 60–75 minutes continuously.

Starting Point

Ideal candidates have finished a 10K and run 20–30 miles per week. Your long run should be at least 60 minutes before week 1. Estimate goal pace with the Race Predictor using a recent 10K or 5K result.

  • Weekly mileage starting point: 20–30 miles
  • Long run baseline: 60–75 minutes
  • At least one tempo or interval session in recent training

Plan Overview

Five runs per week: three easy, one quality (tempo or intervals), one long run. Easy mileage fills the gaps — keep it honest with heart rate or the talk test. See our easy run pace guide if easy days feel too hard.

Weeks 1–4: Aerobic Foundation

Gradually extend the long run and introduce weekly tempo segments. No single week should increase total mileage by more than 10%.

Typical week (Weeks 1–4)

  • MonEasy 40 min
  • TueTempo 20–25 min at HM pace
  • WedEasy 35 min
  • ThuEasy 40 min
  • SatLong run — 70 min (W1), 75 min (W2), 80 min (W3), 65 min easy (W4 recovery)

Weeks 5–8: Build Phase

Long runs reach 85–95 minutes with the final 20–30 minutes at half marathon effort. Tempo runs extend to 30–40 minutes. Add one interval session every other week.

Week 6 example

  • MonEasy 45 min
  • TueTempo 35 min at HM pace
  • WedEasy 40 min
  • Thu4 × 1 mile at 10K pace, 2 min jog
  • SatLong 90 min (last 25 min at HM pace)

Week 8 example (peak week)

  • MonEasy 45 min
  • TueTempo 40 min at HM pace
  • WedEasy 40 min
  • ThuEasy 45 min
  • SatLong 95 min

Weeks 9–12: Sharpen and Taper

Volume drops while intensity stays touchable. Long runs shorten; race-pace segments stay short and sharp.

Week 10

  • MonEasy 40 min
  • Tue3 × 1 mile at HM pace
  • WedEasy 35 min
  • SatLong 75 min

Week 11

  • MonEasy 35 min
  • TueTempo 20 min at HM pace
  • WedEasy 30 min
  • SatLong 60 min

Week 12 (race week)

  • MonEasy 25 min
  • Wed3 × 1K at HM pace
  • FriRest
  • SunHalf marathon

Fueling for Long Runs

Practice race nutrition on every long run over 75 minutes. Aim for 30–60g of carbs per hour — gels, chews, or sports drink. Your gut is a trainable system; race day is not the time to experiment.

Race-Day Execution

Start conservatively. Miles 1–3 should feel almost too easy. Settle into goal pace through the middle miles, then run the second half equal to or faster than the first (negative split). Use the Pace Chart and Calories Calculator to plan pacing and mid-race fueling.

When to Adjust

Miss a week due to illness or travel? Repeat the previous week rather than cramming missed miles. Persistent fatigue, elevated resting heart rate, or nagging pain means an extra recovery day — not another hard session.