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20-week half marathon training plan (variations included)

A 20-week half marathon training plan with week-by-week structure, workouts, adaptation rules, and a pace calculator. Variations are included on one page.

Last updated/Mar 20, 2026, 11:05 PM
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Start here

One decision, then execute

Pick the default variant, scan the phase map, then use one tool to lock pace and fueling numbers.

1. Choose a variant

4 days/week (Beginner-friendly)

Start with the recommended default. Customize only after two consistent weeks.

2. Scan the phase map

Base → build → peak → taper

Use the condensed view, then open the full week-by-week table only when you need detail.

Jump to week-by-week

3. Lock your numbers

Pace + fueling defaults

Run one calculator now so race week is execution, not improvisation.

Jump to tools

At a glance

Plan length

20 weeks

Built with phases, cutbacks, and a taper you can actually execute.

Weekly rhythm

3–6 days/week

Choose one variant and follow it for 2 weeks before tweaking.

Typical session time

Easy: ~45m • Long: ~105m

Prefer consistent minutes over heroic single sessions.

Readiness gate

  • • You can run 30 minutes comfortably 3–4×/week.
  • • You can complete a long-ish session (60–75 min) without being wrecked for 2 days.
  • • You’re willing to keep easy days easy so workouts stay high-quality.

Default recommendation

4 days/week (Beginner-friendly)

Start here to reduce decision fatigue. Customize only after your first two weeks feel stable.

  • • Best if your schedule is tight or you’re building durability.
  • • Keep workouts conservative; consistency is the win.

Safety first

This is general training information, not medical advice.

  • • Pain that changes your gait (scale down and get assessed).
  • • A rapidly increasing injury history with volume increases.
  • • Illness symptoms that worsen with training load.

Coaching beta

Want this adapted to your recovery?

Get coach-style adjustments when you miss sessions, sleep poorly, or feel fatigue signals.

Start Training

Plan variants (days/week)

Pick a weekly rhythm you can repeat consistently. Start with the recommended default, then adjust only after your first two weeks feel stable.

4 days/week (Beginner-friendly)

4 days/week/Beginner
Recommended
  • • Best if your schedule is tight or you’re building durability.
  • • Keep workouts conservative; consistency is the win.

3 days/week (Minimum effective dose)

3 days/week/Beginner
  • • Best if you’re time-limited, returning from time off, or managing impact.
  • • Protect the long run. Keep the workout controlled. Add strength on 1–2 non-run days.

5 days/week (Balanced default)

5 days/week/Intermediate
  • • A strong default: enough volume to progress, enough recovery to absorb it.
  • • One workout + one long run focus per week is plenty.

6 days/week (Advanced, recovery-dependent)

6 days/week/Advanced
  • • Only if your recovery stays stable for 2–3 weeks in a row.
  • • The extra day should be truly easy or short recovery.

How to use this plan

This page is a plan cluster: pick one days/week variant and execute it for 2 weeks before tweaking. Keep easy runs easy so you can absorb the long run and one quality session.

Sample weekly schedules (3–6 days/week)

These are example templates. You can move days around, but keep this order: workout → recovery → long run.

3 days/week (minimum effective dose)

  • Day 1: Easy run + 4–6 strides (optional)
  • Day 2: Quality workout (controlled)
  • Day 3: Long run (easy; practice fueling on longer days)

4 days/week (beginner-friendly)

  • Day 1: Easy run + short strength
  • Day 2: Quality workout (controlled)
  • Day 3: Easy run (keep it truly easy)
  • Day 4: Long run (easy; progress slowly)

5 days/week (balanced default)

  • Day 1: Easy run
  • Day 2: Quality workout
  • Day 3: Easy run + short strength
  • Day 4: Easy run (or steady when recovered)
  • Day 5: Long run

6 days/week (advanced)

  • Add one extra short recovery run (very easy).
  • Keep the number of hard sessions the same; the extra day is for aerobic volume, not intensity.

Run/walk option (allowed)

Run/walk is a durability tool — not a failure mode. Use it to keep easy days easy and protect recovery.

  • Keep intensity low (conversation test).
  • Progress one variable at a time (longer run intervals before faster pace).
  • On long runs, aim for repeatable time on feet without being wrecked for 48 hours.

Guide: Run/walk marathon training plan

If you’re over 50 (masters runners)

The plan is the same; the recovery math changes.

  • Keep easy days truly easy so workouts stay effective.
  • Treat strength as part of training (2 short sessions/week is high-ROI).
  • If niggles accumulate, reduce intensity first — not sleep.

Guide: Marathon training plan over 50

Training for a time goal (sub-4 / sub-2 / PRs)

Use pace tools to translate a goal into numbers — then train by effort on easy days so you can absorb the hard work.

Guide: Sub-2 hour half marathon training plan

Common glossary terms (so the plan language is clear):

Week by week

Structure you can scan

Use this as your decision map: what matters this week, what the long run is doing, and where you should back off.

BaseJump

Weeks 1–5

Build consistency and durable easy volume.

Long session: 1h long run (steady finish when recovered) • Cutbacks: 1

BuildJump

Weeks 6–13

Add quality while protecting recovery.

Long session: 1h 20m long run (steady finish when recovered) • Cutbacks: 2

PeakJump

Weeks 14–17

Train race-specific pacing and fueling.

Long session: 1h 53m long run (steady finish when recovered) • Cutbacks: 1

TaperJump

Weeks 18–20

Reduce load; keep rhythm; arrive fresh.

Long session: 1h 40m long run (steady finish when recovered)

View full week-by-week table
WeekPhaseFocusLong sessionKey workoutsNotes
1BaseBuild consistency and durable easy volume.1h long run (steady finish when recovered)Strides + controlled aerobic • Hill sprints (short) + strength—
2BaseBuild consistency and durable easy volume.1h 4m long run (steady finish when recovered)Strides + controlled aerobic • Hill sprints (short) + strength—
3BaseBuild consistency and durable easy volume.1h 8m long run (steady finish when recovered)Strides + controlled aerobic • Hill sprints (short) + strength—
4BaseBuild consistency and durable easy volume.1h 1m long run (steady finish when recovered)Strides + controlled aerobic • Hill sprints (short) + strengthCutback week
5BaseBuild consistency and durable easy volume.1h 16m long run (steady finish when recovered)Strides + controlled aerobic • Hill sprints (short) + strength—
6BuildAdd quality while protecting recovery.1h 20m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
7BuildAdd quality while protecting recovery.1h 24m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
8BuildAdd quality while protecting recovery.1h 15m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progressionCutback week
9BuildAdd quality while protecting recovery.1h 33m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
10BuildAdd quality while protecting recovery.1h 37m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
11BuildAdd quality while protecting recovery.1h 41m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
12BuildAdd quality while protecting recovery.1h 29m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progressionCutback week
13BuildAdd quality while protecting recovery.1h 49m long run (steady finish when recovered)Tempo or cruise intervals • Long-run progression—
14PeakTrain race-specific pacing and fueling.1h 53m long run (steady finish when recovered)Threshold + speed endurance • Long run with controlled finish—
15PeakTrain race-specific pacing and fueling.1h 57m long run (steady finish when recovered)Threshold + speed endurance • Long run with controlled finish—
16PeakTrain race-specific pacing and fueling.1h 43m long run (steady finish when recovered)Threshold + speed endurance • Long run with controlled finishCutback week
17PeakTrain race-specific pacing and fueling.2h 5m long run (steady finish when recovered)Threshold + speed endurance • Long run with controlled finish—
18TaperReduce load; keep rhythm; arrive fresh.1h 40m long run (steady finish when recovered)Short tempo + strides • Easy aerobic + sleep focus—
19TaperReduce load; keep rhythm; arrive fresh.1h 15m long run (steady finish when recovered)Short tempo + strides • Easy aerobic + sleep focus—
20TaperReduce load; keep rhythm; arrive fresh.56 min long run (steady finish when recovered)Short tempo + strides • Easy aerobic + sleep focus—

Workout library

The sessions you repeat

You don’t need 50 workouts. You need a small library that you execute consistently, then progress safely.

Easy aerobic run

Purpose: Build volume without accumulating fatigue.

Prescription: 30–60 min at conversational effort. If you can’t talk in full sentences, it’s too hard.

Substitutions

  • • Bike or easy elliptical for the same time if impact is an issue.

Red flags

  • • Pain that changes your gait.
  • • Easy pace drifting harder to hold the same effort.
Strides + drills

Purpose: Improve mechanics and economy without a heavy metabolic cost.

Prescription: After an easy run: 6–10 × 15–20 sec fast-but-relaxed, full walk/jog recovery.

Substitutions

  • • 6–8 × 20 sec hill strides for reduced impact.

Red flags

  • • Sprint-like intensity that leaves you sore.
  • • Tight hamstrings or sharp calf pain.
Tempo / cruise intervals

Purpose: Raise sustainable pace and teach controlled discomfort.

Prescription: 2–4 × 8–12 min at ‘comfortably hard’ with 2–3 min easy between.

Substitutions

  • • 20–30 min steady tempo continuous if you pace well.

Red flags

  • • Breathing out of control early.
  • • Needing to ‘surge’ to hold the last reps.
Interval session (VO₂-ish)

Purpose: Sharpen speed and economy for faster running at a lower cost.

Prescription: 5–8 × 3 min hard with 2–3 min easy; stay controlled, finish with form.

Substitutions

  • • 6–10 × 400m on the track with equal jog recovery.

Red flags

  • • All-out reps.
  • • Form collapse or sharp pains.
Long run (easy with structure)

Purpose: Build durability and rehearsals for race-day pacing and fueling.

Prescription: Mostly easy. When stable: finish the last 15–25 min steady (not a race).

Substitutions

  • • Split long run (AM/PM) on high-stress weeks; keep total time similar.

Red flags

  • • Long-run pace creeping; next-day fatigue lasting >48h.
  • • Fueling causing repeated GI issues (adjust and practice).
Threshold + fast finish

Purpose: Practice the exact intensity you want to execute on race day.

Prescription: 3 × 10 min threshold, then 10–15 min steady finish if you’re recovered.

Substitutions

  • • Progression run: easy → steady → controlled hard (only when recovered).

Red flags

  • • Needing to ‘push’ early.
  • • Shin/calf pain that escalates with pace.
Strength (short + consistent)

Purpose: Support durability and running economy with minimal interference.

Prescription: 2×/week, 20–35 min: hips, calves, hamstrings, trunk. Leave 1–2 reps in the tank.

Substitutions

  • • Bodyweight circuit if you’re traveling.

Red flags

  • • Heavy DOMS that ruins key sessions.
  • • Form breakdown under load.

Adaptation rules

What to do when life happens

Most training failures are not fitness failures — they’re pacing, sleep, or scheduling failures. Use simple rules.

Missed workout

  • • Don’t ‘make up’ missed sessions by doubling hard days.
  • • If you miss one workout: keep the long run, skip the extra intensity.
  • • If you miss a week: repeat the last week you completed confidently.

Low sleep week

  • • Cut intensity before you cut easy volume: keep it aerobic.
  • • Shorten the long run by 15–25% if sleep is poor for multiple nights.
  • • Add one extra rest day if stress is high.

Fatigue signals

  • • If your easy pace feels hard: keep the day easy and shorten duration.
  • • If soreness persists >48h: remove the next hard session.
  • • If motivation tanks + HR drifts: treat it like a recovery week.

Pain or injury

  • • Pain that changes form is a stop signal — do not ‘push through’.
  • • Swap running for low-impact cardio until pain-free in daily life.
  • • Return with short easy runs; add intensity last.

Travel week

  • • Protect one key session: either the long run or the workout — not both.
  • • Use time-based training (minutes) when terrain/schedule changes.
  • • Keep strength micro-sessions (10–15 min) instead of skipping completely.

Tools

Numbers to train with

Pick one tool, generate outputs, then plug them into your training week.

Loading pace calculator…
Loading race time predictor…
Running pace calculator
Open the calculator with defaults tuned to this plan.
Race time predictor
Open the calculator with defaults tuned to this plan.

Evidence (high level)

Why this structure works

  • • Consistency beats hero sessions: durable aerobic volume is the engine.
  • • Cutback weeks reduce injury risk and help you absorb training.
  • • A small workout library repeated with progression is more effective than endless novelty.
  • • Fueling practice is a skill — you train it like pacing.

FAQs

Is a 20-week half marathon plan enough time?

For many runners with a base, yes. If you’re building from low mileage or returning from injury, extend the timeline and keep intensity conservative.

How many hard sessions should I do per week?

A good default is one quality workout plus one long-run focus. If you add more, it should be short and only when recovery is stable.

What if I miss a run?

Don’t cram. Keep the next session easy, protect the long run, and resume structure when your legs feel normal again.

How do I keep easy runs truly easy?

Use a conversational effort check: you should be able to talk in full sentences. If not, slow down or add walk breaks.

Do I need strength training?

Two short sessions per week is a high-ROI habit for durability. Keep it consistent and avoid leaving yourself sore for key runs.

When should I practice fueling?

For half marathons, fueling is simpler, but practicing hydration and pre-run carbs still helps you race consistently.

Keep going

Half Marathon Training Hub

Half marathon training plans, pacing tools, and guides — structured to reduce overwhelm and keep training simple.

Running Pace Calculator (with Splits)

Convert distance + time into pace per km/mile and generate a splits table. Useful for planning workouts and race pacing.

Race Time Predictor (Riegel Model)

Estimate equivalent 5K/10K/half marathon/marathon times from one known result using a simple model. Useful for goal-setting and pacing.

Best Marathon Training Plan (Decision Tree + How to Choose)

A practical decision tree to pick the best marathon training plan for you — based on your base, recovery, and constraints.

Sources