How long to train for a half marathon
If you comfortably run 5 km three or four times a week, 12 weeks is enough; the exact time depends on how much you run today.
| Where you are now | How long to train |
|---|---|
| Not running at all | 21 weeks or more: 9 weeks to 30 minutes of running, then a 12-week plan |
| Running 5 km three or four times a week | 12 weeks |
| Running 10 km regularly | 8 to 12 weeks: you can start the plan at week 5, with a 9.7 km long run |
| You have run a half marathon and want to go faster | 12 weeks, as in Higdon's plans for experienced runners |
The times in the table follow Hal Higdon's Novice 1 plan and the NHS Couch to 5K program: a guide, not a guarantee of readiness. Novice 1 takes 12 weeks and is laid out below.
Can you train for a half marathon from zero?
Yes, but not in 12 weeks: Higdon designed his 12-week plan for people who already run 4.8 km three or four times a week, and advises those who find that hard to pick a shorter first race.
The path from zero starts with a base: the NHS Couch to 5K program takes a beginner to 30 minutes of non-stop running in 9 weeks. Learn to run 30 to 40 minutes comfortably, and only then take on a half marathon plan. With the 12-week plan that is at least 21 weeks, and a margin helps: the NHS openly allows taking longer than 9 weeks.
The 12-week training plan
For a first half marathon, Hal Higdon's Novice 1 works well: 12 weeks, four runs a week, the long run growing from 6.4 to 16.1 km.
Monday and Friday are rest days. Tuesday and Thursday are easy runs, Wednesday is a short run or cross training, Saturday is 30 to 60 minutes of swimming, cycling or walking, Sunday is the long run. In week 6 a 5K race replaces the long run, in week 9 a 10K.
Show the week-by-week plan
| Week | Weekday runs, km | Long run | Total, km |
|---|---|---|---|
| 1 | 4.8, 3.2, 4.8 | 6.4 km | 19.2 |
| 2 | 4.8, 3.2, 4.8 | 6.4 km | 19.2 |
| 3 | 5.6, 3.2, 5.6 | 8.1 km | 22.5 |
| 4 | 5.9, 3.2, 5.9 | 8.1 km | 23.1 |
| 5 | 6.4, 3.2, 6.4 | 9.7 km | 25.7 |
| 6 | 6.4, 3.2, 6.4 | race: 5K | 16 + race |
| 7 | 7.3, 4.8, 7.3 | 11.3 km | 30.7 |
| 8 | 7.3, 4.8, 7.3 | 12.9 km | 32.3 |
| 9 | 8.1, 4.8, 8.1 | race: 10K | 21 + race |
| 10 | 8.1, 4.8, 8.1 | 14.5 km | 35.5 |
| 11longest | 8.1, 4.8, 8.1 | 16.1 km | 37.1 |
| 12 | 6.4, 4.8, 3.2 | race: half marathon | 14.4 + race |
Volume grows from 19.2 km in week one to 37.1 km in week eleven. Pace does not matter: Higdon asks you to run at a conversational pace and to walk when you are tired. You can move runs between days; consistency matters more. For 2027 races with a confirmed date, the plan is laid out by date in the race calendar.
Train for your half marathon on your own plan
The table above is a generic framework: it knows nothing about your base, your race date or your goal. Pacero, an iPhone app, builds a plan for your race and goal time from your current level, spreads the load across the weeks and updates the plan after your runs. Workouts from Apple Watch, Garmin and other watches come in through Apple Health; without a watch, record runs with GPS in the app, log them by hand or upload a screenshot.
Train with Pacero →First 7 days free, no card needed.How much to run each week
For a first half marathon, the peak week in Novice 1 is up to 37 km over four runs. In Intermediate 1, for those who want to run faster, it is about 55 km over five. These are guidelines, not an entry ticket: people tolerate load differently.
| Aim (Higdon plan) | Peak week | Runs |
|---|---|---|
| Finish (Novice 1) | up to 37 km | 4 |
| Run faster (Intermediate 1) | about 55 km | 5 |
Injuries during training are common: of 735 New York City Marathon entrants, 40% reported an injury during 16 weeks of training. The "no more than 10% a week" rule is a handy brake, not a law: at 15 km a week it gives a tiny step, and at 80 km it can be too much.
A single run's jump predicts injury better: in data from 5,205 runners, risk rose when a run was more than 10% longer than the longest run of the previous 30 days, while weekly volume growth did not raise risk in that data. Do not suddenly run long if recent weeks have not led up to it. Even Higdon's long run steps exceed 10%, so if the next one feels hard, repeat the previous one.
Types of workouts: easy runs, long runs, tempo, intervals
Half marathon training uses four types of runs: easy runs, the long run, tempo runs and intervals. A first-race plan needs only the first two; plans for experienced runners add tempo runs and intervals.
Easy run
Most of your volume. Conversational pace: if you cannot talk, you are running too fast.
Long run
The key workout. Higdon advises running it 30 to 90 seconds per mile, roughly 19 to 56 seconds per kilometer, slower than goal pace.
Tempo run
A continuous 30 to 45 minutes: 10 to 15 minutes easy, 15 to 20 minutes building gradually to near 10K pace, 5 to 10 minutes easy.
Intervals
400 m repeats at 5K or 10K pace, with walking or jogging between them. Higdon uses 5 to 10 repeats.
One more type is the race pace run: a few kilometers at your half marathon goal pace to get used to it. The pace calculator works out the pace for your half marathon, 10K and 5K goals.
Most training is easy running. In Seiler and Kjerland's study, national-level junior skiers did about 75% of their sessions at low intensity, 8% in the middle zone and 17% at high intensity; this is where the popular "80/20" guideline comes from. With three or four runs a week, one quality session is usually enough.
Strength and cross training
Cross training is an easy day without running: swimming, cycling, walking or skiing, to recover from your runs. Novice 1 gives it Saturday, 30 to 60 minutes.
Higdon advises against starting strength training in the middle of a plan if you have never lifted weights: wait until the plan is over. If you already lift, keep going, but you can ease off near the end of the cycle when volume rises. Tuesday and Thursday work well, after a run, not before; for runners he recommends light weights and many reps.
Heart rate zones for running
An easy run is 65 to 75% of maximum heart rate: that is the range Higdon gives for all conversational-pace runs.
The familiar "220 minus age" formula underestimates the maximum in older people. According to Tanaka and colleagues' meta-analysis, 208 − 0.7 × age is more accurate: at 40 that is 180 beats per minute, and an easy run is 117 to 135. The formula gives an average for your age, not your personal maximum.
| Zone | % of maximum | How it feels |
|---|---|---|
| 1 | 50 to 60% | Relaxed, even breathing |
| 2 | 60 to 70% | Comfortable, you can talk |
| 3 | 70 to 80% | Moderate, harder to talk |
| 4 | 80 to 90% | Fast and uncomfortable, heavy breathing |
| 5 | 90 to 100% | Sprint pace, not sustainable for long |
This breakdown comes from the Garmin fēnix 7 manual; other watches and coaches draw zone borders differently. Higdon's easy run is the top of zone two and the bottom of zone three. Without a watch the rule is the same: on an easy run you can talk.
How to choose your half marathon goal and pace
The easiest starting point is a recent 10K: by the Riegel formula your half marathon time is about 2.21 times longer.
| Half marathon goal | Pace/km | 10K by Riegel |
|---|---|---|
| 2:30:00 | 7:06 | 1:07:59 |
| 2:15:00 | 6:23 | 1:01:11 |
| 2:00:00 | 5:41 | 54:23 |
| 1:45:00 | 4:58 | 47:35 |
| 1:30:00 | 4:15 | 40:47 |
The formula assumes the long runs and tempo runs are done; without them the prediction is too optimistic, especially from a 5K. In a first half marathon the main aim is an even finish; time comes second.
Without a recent race, compare yourself with others: average times and a pace chart are in how long it takes to run a marathon and half marathon, and average 10K times in 10K times. To choose between "just finish" and a specific time, see the guide to choosing a race goal. The next step after a half marathon is marathon training.
The taper
The taper is the last one or two weeks before the race: volume drops, your usual intensity stays.
In Novice 1 it is short: the longest run, 16.1 km, comes a week before the race, and race week has 6.4, 4.8 and 3.2 km. For experienced runners, a meta-analysis of 27 studies in competitive athletes is a useful guide: the best average result came from a two-week taper cutting volume by 41 to 60% without reducing intensity. It is a guideline, not an individual prescription.
Fueling and water on the course
If your half marathon takes one to 2.5 hours, aim for 30 to 60 g of carbohydrate per hour: a gel, a drink or familiar food; the total carbs count, not the number of packs. For a 45 to 75 minute race, small amounts are enough, even rinsing your mouth with a sports drink.
If you expect to run longer than 90 minutes, the ACSM advises 10 to 12 g of carbohydrate per kilogram of body weight per day for 36 to 48 hours before the race: 700 to 840 g for a 70 kg runner, from oats, rice, pasta and bread. Breakfast goes 1 to 4 hours before the start, 1 to 4 g of carbohydrate per kilogram; avoid fatty, high-protein and high-fiber food to spare your stomach.
Drink so that you lose no more than 2% of body weight, but no more than you sweat out: excess water lowers the sodium level in your blood, which is hyponatremia. Weighing yourself before and after a long run shows how much you lose. Rehearse all of this on long runs.
Race tactics
Run evenly: the first kilometers at goal pace or slightly slower.
A common mistake is starting too fast: fresh legs, the crowd and adrenaline pull you ahead of plan, and you pay at the end. In the Vienna City Marathon half marathon from 2006 to 2018 (133,268 finishers), every group slowed down over the distance, most of all between 15 and 20 km. The fastest quarter changed speed about half as much as the slowest: around 3% against 5.5 to 6%. The calculator works out splits for your pace.
Walking is fine: Higdon considers it a normal strategy for finishing and advises walking through aid stations, where it is easier to drink. If you race for time, warm up: before a race Higdon jogs 1 to 2 miles (1.6 to 3.2 km), stretches for 5 to 10 minutes and does a few 100 m strides near race pace.
Recovery after a half marathon
Skip hard training for the first two days: in a study of 36 amateur runners who ran a half marathon on a treadmill at a comfortable pace, muscle strength and running mechanics returned to normal within a day, and hip position sense within two.
Fatigue lasts at least a day. In another study of 46 male amateur runners after a half marathon, 15 minutes of jogging right after the finish did not help: the runners felt less recovered. Massage and a cold bath reduced muscle soreness but did not change objective measures. After that, return to easy running as you feel.
Common mistakes and when to cut back
The usual culprits are skipped long runs, treating every run as a speed test, and new gels, shoes or clothing tried for the first time on race day.
Persistent fatigue, poor sleep, slower usual pace at the same effort and a resting heart rate above normal are reasons to cut back. Pain that changes your running form, gets worse with training or does not ease at rest is a reason to stop and see a doctor or sports physiotherapist.
Quick answers
How long does it take to train for a half marathon from zero?
At least about 5 months: 9 weeks of Couch to 5K to reach 30 minutes of non-stop running, then a 12-week plan. With a 5K base, 12 weeks is enough; if you run 10K regularly, 8 to 12.
How many kilometers a week should I run?
In Higdon's plan for a first half marathon the peak week is up to 37 km over four runs; in Intermediate 1, for those who want to go faster, about 55 km over five.
Do I need to run 21 km in training?
No. In Higdon's first half marathon plan the longest run is 16 km; in plans for experienced runners, 12 miles, about 19 km.
How do I work out my half marathon goal pace?
Multiply a recent 10K time by about 2.21 and divide the prediction by 21.1. It is a starting point, not a promise.
Do I need gels for a half marathon?
If you run for one to 2.5 hours, aim for 30 to 60 g of carbohydrate per hour: gels, a drink or familiar food. Test them on long runs, not on race day.
How long should I recover after a half marathon?
Skip hard training for the first two days, then return to easy running as you feel.
Sources
- Hal Higdon: Half Marathon Novice 1: the 12-week plan, weekly structure, starting level, heart rate at 65 to 75% of maximum, cross training and strength, races in weeks 6 and 9.
- Hal Higdon: Half Marathon Intermediate 1 and Intermediate 2: long run pace, tempo runs, 400 m intervals, race pace runs, warm-up, strength, walking, long runs up to 12 miles, the Intermediate 1 peak week.
- NHS: Couch to 5K: 9 weeks (or longer) to 30 minutes of non-stop running.
- Toresdahl et al., 2023: injuries in 735 New York City Marathon entrants.
- Frandsen et al., 2025: single-run distance spikes in a cohort of 5,205 runners.
- Seiler & Kjerland, 2006: intensity distribution in trained athletes.
- Tanaka et al., 2001: maximum heart rate 208 − 0.7 × age.
- Garmin fēnix 7 owner's manual: Heart Rate Zone Calculations: five zones as a percentage of maximum heart rate.
- Peter Riegel, 1981: the original time prediction formula.
- Bosquet et al., 2007: meta-analysis of taper strategies.
- ACSM, Nutrition and Athletic Performance, 2016: carbohydrate before and during exercise of different lengths.
- ISSN position stand, 2008: 30 to 60 g of carbohydrate per hour during exercise.
- ACSM, Exercise and fluid replacement, 2007: water loss under 2% of body weight, hyponatremia risk.
- Ristanović et al., 2023: split pacing in 133,268 Vienna half marathon finishers.
- Wang et al., 2025: recovery of 36 amateur runners after a treadmill half marathon.
- Wiewelhove et al., 2018: recovery methods after a half marathon in 46 amateur runners.