Most half marathon training plans run 10 to 14 weeks, with 12 weeks being the most common starting point for runners who already have a base of fitness. Complete beginners who aren’t yet running regularly may need 16 to 20 weeks. Experienced runners chasing a personal record typically use 12 to 16 weeks. The right number for you depends almost entirely on where your fitness is today.
Training Duration by Experience Level
If you can already run about 3 to 4 miles comfortably, a 12-week plan gives you enough time to build up to 13.1 miles safely. If you can run a 5K right now, some coaches say eight weeks is technically possible, but most recommend at least three to four months to build in a buffer for illness, minor injuries, or life getting in the way.
For true beginners starting from little or no running background, a 20-week plan is a better fit. These extended plans spend the early weeks building the habit of running consistently before shifting into half marathon-specific training. A 14-week plan splits the difference and works well if you’ve been running casually but haven’t followed a structured program before.
Intermediate and advanced runners targeting a faster finish time generally train for 12 to 16 weeks. The extra weeks aren’t about building endurance (they already have it) but about layering in speed work and race-pace sessions that take time to produce results. These plans typically call for 3 to 4 runs per week at higher intensities.
Build a Base Before You Start
A training plan assumes you show up on week one ready to handle its starting workload. If you can’t, you need a base-building phase first, and that adds weeks to your total timeline.
Running coach guidelines suggest beginners spend 10 to 12 weeks building a base before starting a formal plan. Intermediate runners need 6 to 10 weeks, while advanced runners coming off a recent training cycle can get by with 4 to 8 weeks. The goal of base building is to add roughly 10 to 15 miles per week beyond where you are now. A practical benchmark: by the end of your base phase, you should be running about 80% of whatever week one of your chosen plan requires. So if your plan starts at 20 miles for the week, you want to be comfortable at around 16 miles before day one.
This means a complete beginner who isn’t running at all might realistically need 22 to 32 weeks from their first run to race day: 10 to 12 weeks of base building plus 12 to 20 weeks of structured training.
What a Typical Week Looks Like
A beginner plan like Hal Higdon’s popular Novice 1 program has you running 4 days per week, with distances ranging from 3 to 10 miles across the 12 weeks. The remaining days are rest or optional cross-training. The weekly structure is straightforward: a few shorter runs during the week and one longer run on the weekend.
That long run is the backbone of your training. It starts around 3 to 4 miles in week one and increases gradually each weekend, peaking at about 10 miles before the race. You never actually run 13.1 miles in training. After your longest run, you scale back for a brief taper period, and race-day adrenaline plus your accumulated fitness carry you the final distance.
Intermediate plans add one dedicated speed session per week, usually on a midweek day. These alternate between tempo runs (sustained efforts of 30 to 45 minutes with the hard portion in the middle) and interval workouts on a track. A common interval progression starts with 5 repeats of 400 meters in week one and builds to 10 repeats by the final weeks. The tempo runs gradually lengthen from 30 to 45 minutes as the plan progresses.
How Long Runs Progress Week to Week
Your long run doesn’t increase every single weekend. Most plans follow a pattern of building for two or three weeks, then pulling back for a recovery week before building again. This sawtooth pattern lets your body absorb the training stress rather than just accumulating fatigue.
The popular “10% rule,” which says you shouldn’t increase weekly mileage by more than 10% at a time, is deeply embedded in running culture but has less scientific support than most runners assume. A large study of over 5,200 runners published in the British Journal of Sports Medicine found no clear relationship between week-to-week mileage changes and injury risk. What did matter was the distance of individual sessions. In practical terms, this means avoiding a single massive long run that’s far beyond what you’ve done recently is more important than obsessing over your total weekly percentage increase.
Still, gradual progression remains common sense. Most 12-week plans increase the long run by about a mile each building week, topping out at 10 to 12 miles two to three weeks before race day.
The Taper Before Race Day
Every half marathon plan ends with a taper, a period where you deliberately run less so your body can recover and arrive at the starting line fresh. For a half marathon, the taper lasts about 2 weeks (compared to 2 to 3 weeks for a full marathon). During each taper week, you cut your total mileage by roughly 20 to 30% from the previous week while maintaining the same intensity on your remaining runs.
The taper feels counterintuitive. After months of building, cutting back can make you restless or worried about losing fitness. You won’t. Fitness doesn’t disappear in two weeks, and the recovery you gain is worth far more on race day than one extra long run would be.
Recovery After the Race
Planning your training timeline also means knowing what comes after. Half marathon recovery is relatively quick compared to a full marathon. Research from 2025 found that muscle strength returns to normal within about 48 hours of finishing a half marathon.
A reasonable post-race schedule looks like this: one day of complete rest, a day of low-impact activity like cycling or an elliptical session, then a couple of easy runs before returning to normal training around day five. Most runners are fully back to their regular routine within a week, with rest days sprinkled in over the following two weeks as a precaution.
Picking the Right Plan Length for You
The simplest way to choose is to work backward from your race date and be honest about your current fitness:
- Not currently running at all: Give yourself 20 weeks minimum, ideally with a base-building phase before that.
- Running 2 to 3 miles a few times per week: A 14-week plan gives you comfortable room to build.
- Comfortably running 4 to 6 miles: A standard 12-week plan is a strong fit.
- Experienced runner targeting a PR: 12 to 16 weeks focused on speed development.
If your race is sooner than these timelines allow, it’s better to pick a later race than to compress a plan. Skipping weeks or combining workouts is where injuries happen. Three to four months is the sweet spot for most people, providing enough time to train thoroughly while keeping the goal close enough to stay motivated.