How Many Weeks to Train for a Half Marathon?

How many weeks to train for a half marathon? Most first-time runners need about 12, provided they can already run roughly 5K (3 miles) three times a week. From no running at all, add the 9-week Couch to 5K first, which makes about 21 weeks. The plan below opens at 12 weeks and goes from 8 to 20.

Choose the length, runs per week and level, and the generator lays out every week with the run type and distance. Add a goal time and each run gets a pace. The sections below show what each plan length changes and what the last two weeks look like.

Everything is calculated in your browser, so nothing you type is uploaded, and the tool is free with no account or sign-up.

Want this on your phone? Get the RunPacePlan app for Android; the iPhone version is coming soon.

How to use the half marathon plan generator

1. Race is set to half marathon. Plan length opens at 12 weeks; choose anything from 8 to 20.
2. Pick Runs per week (3, 4, 5 or 6) and Level (Beginner, Intermediate or Advanced).
3. Enter a Goal time (optional) to put a pace on every run, and a Race date (optional) to date each run.
4. Read the summary line (peak week and longest run), then the weeks, shown as seven day boxes.
5. Choose miles or km with the Units switch; every distance in the plan changes with it and your choice is remembered.
6. Use Print, Download PDF, Add to calendar (.ics) or Copy link.

The plan is made in your browser and nothing you type is uploaded. Saving and syncing plans are not available yet. Prefer your phone? There is a RunPacePlan app for Android, with the iPhone version coming soon.

Change one setting at a time to see its effect. Lengthen the plan and the weekly steps get smaller; add a run day and the peak week rises; move from Beginner to Intermediate and both the peak week and the number of hard sessions go up. With a goal time every run shows a pace, and with a race date every run shows its day.

How long should I train for a half marathon from a 5K, a 10K or nothing?

Start from the distance you can run now. If you can run about 5K without stopping three times a week, 12 weeks is enough for a first half marathon. From about 10K, 8 to 10 weeks can work. From no running, do the Couch to 5K and then a 12-week plan, or pick a 16 to 20 week plan.

This is our own rule of thumb. For comparison, Hal Higdon’s Novice 1 half marathon program runs 12 weeks and assumes you can already run 3 miles, three to four times a week.

What do 10, 12, 16 and 20 weeks change?

Less than you might expect for the peak, and more for how steeply you get there. In this tool a beginner plan reaches its ceiling at 12 weeks: a 12-week and a 20-week beginner plan both peak at 21.1 miles (34 km) with a longest run of 8.5 miles (14 km). The extra weeks make each weekly step smaller. The table is for four runs a week.

The advanced rows are high because that level starts from a bigger base. Choose Beginner unless you already run regularly.

What happens in the last two weeks?

The last two weeks are the taper: the week before race week is at 75% of the peak week and race week at 50%, ending with the race. Every plan also has a cutback week at about 80% of the week before it, every fourth week, and no hard session on the day before or after the long run.

Who is each plan length for?

Twelve weeks suits a runner who already runs about 5K three times a week. Sixteen to twenty weeks suits someone who wants smaller weekly steps or is returning from a break. Eight to ten weeks only suits a runner who already covers 10K comfortably.

What mistakes do people make with plan length?

Choosing a plan shorter than their base allows, then squeezing the week-to-week jumps. Skipping the cutback week, which falls every fourth week at about 80%. Adding a long run in race week.

How does a half marathon plan compare with a marathon plan?

A half marathon plan here tapers for 2 weeks and a marathon plan for 3. The 12-week intermediate half peaks at 28.8 miles (46 km), while the 16-week intermediate marathon peaks at 39.6 miles (64 km). See how many weeks to train for a marathon.

Frequently asked questions

How many weeks should I train for a half marathon?

12 weeks for most first-timers who can already run about 5K. The generator offers 8 to 20 weeks, so shorten it if you run 10K now and lengthen it if you want gentler steps.

Can I train for a half marathon in 12 weeks?

Yes, if you can already run about 5K without stopping three times a week. Hal Higdon’s Novice 1 program uses 12 weeks with the same assumption. If you are starting from nothing, 12 weeks is too short; use the Couch to 5K first.

How long does it take to train for a half marathon as a complete beginner?

About 21 weeks: 9 weeks of Couch to 5K, then a 12-week plan. Build up gradually and ask a doctor first if you have a health condition.

How many runs a week do I need?

The generator offers 3, 4, 5 or 6 runs a week and opens on 4. Pick the number you can keep up every week; hard sessions are never placed the day before or after the long run.

Why taper before a half marathon?

A taper cuts the distance in the last two weeks so your legs recover from training before the race. In this tool the taper weeks are at 75% and 50% of the peak week.

Is the plan free, and do I need an account?

Yes, it is free and needs no account. It runs in your browser and nothing you type is uploaded.

Can I use the plan commercially, for example with runners I coach?

Yes. The schedule, the printout and the calendar file you make here are free to use for any purpose, including giving them to runners you coach, with no credit needed. You may not copy the generator or the site itself; see the terms.

Take this question with you

The RunPacePlan app puts the plan, the paces and the splits for this question on your phone: get it on Google Play. The iPhone version is coming soon.

Related questions

• How Many Weeks to Train for a Marathon?: Another question runners ask.
• What Pace Is a Sub 2 Hour Half Marathon?: Another question runners ask.
• What Pace for a 30 Minute 5K?: Another question runners ask.
• What Is My Easy Run Pace Based on My 5K Time?: Another question runners ask.
• How Many Miles a Week to Run a Marathon?: Another question runners ask.

Related tools

• Half marathon training plan: The full generator with every option.
• 12 week half marathon training plan: A 12-week schedule for race day three months away.
• Couch to 5K plan: Nine weeks of run-walk if you are not running yet.
• 10K training plan: A stepping stone if you run 5K now.
• Half marathon pace chart: Pace and splits for finish times from 1:00 to 3:30.