How Far Should You Run Before A Half Marathon Or Marathon?

The half marathon is one of the most popular distances for runners of all experience levels and abilities. Some runners have the goal of finishing, while others want to earn a PR. Depending on your experience and goals, training for a half marathon will vary. How many miles you run per week, how many days per week you run, and your longest training run before a half marathon all are dependent on current fitness and background.

This article will help you determine the right length for your long run before a half marathon. Before offering guidelines, we’ll first look at common training practices and what current research says. At the end, you will find suggestions on how to extend your long run distance in half marathon training.

Table of contents

• How Far Should You Run Before a Half Marathon, Per Popular Training Methods?
• The Science Behind Half Marathon Training Long Runs
  • Novice runners: 10-11 miles (16-17 km)
  • Intermediate runners: 12-13 miles (19-21 km)
  • Experienced runners: 14-16 miles (23-26 km)
  • Overdistance considerations
• More Advice on Half Marathon Training
  • How Many Miles per Week for a Half Marathon?
  • How Long Should I Train for a Half Marathon?
• Run Your Best Half Marathon Yet

How Far Should You Run Before a Half Marathon, Per Popular Training Methods?

Many beginner plans are designed for just finishing a half marathon — not aiming for a certain time. For that reason, most of these plans do not cover the full half marathon distance in training.

• The Hansons Half-Marathon Method Beginner Plan calls for long runs up to 12 miles (19-20 km). For most of the plan, you alternate between a long run of 10 miles (16 km) and a long run of 12 miles each week.
• The Hal Higdon Novice 1 Half Marathon Training Plan peaks at a 10 mile long run (16 km) the week before the race. His Novice 2 Half Marathon plan includes a 12 mile (19km) long run the week before the race.
• The Jeff Galloway Run-Walk Half Marathon beginner plan brings runners up to 14 miles (22.5 km) (with run/walk intervals) two weeks before the race.
• The McMillan Running Novice 1 Plan peaks with a long run of 105-120 minutes.

Many of these training methodologies also offer training plans for intermediate to advanced runners. In these plans, a typical longest long run is 14 miles.

• The Hal Higdon Advanced Plan reaches a peak long run distance of 2 hours – which may be 13 miles or more depending on the runner.
• The Hansons Half Marathon Method reaches a peak long run of 14 miles for its advanced plan.
• McMillan Running’s intermediate/advanced plan has a peak long run of 14-18 miles (25-30 km).

However, as many runners know, your individual training may vary from generalized training plans – so let’s look into exactly how far you should run before a half marathon based on your current training and fitness.

The Science Behind Half Marathon Training Long Runs

A 2020 study published in the Scandinavian Journal of Medicine and Science in Sports studied how training volume and the longest run in training impacted half marathon performance and running injuries. It uses a sample size of 556 half-marathon runners and ran statistical tests on based on questionnaires and race outcomes. The participants were 61% male, 39% female, and averaged five years of running experience.

The statistical analysis revealed that the longest run of half marathon training did impact race outcome – without increasing the risk of a running injury.

• Half marathon runners who ran <15 km (<9.3 miles) as their longest run finished in an average of 2:06:48.
• Those who completed long runs of 15-21 km (9.3-13 miles) finished in an average of 2:03:28.
• Only 26.3% of the participants ran >21 km (13 miles) in training – and had an average finish time of 1:51:31.

The longest long run also correlated with improved fatigue resistance. Fatigue resistance is the ability to continue to hold your pace/intensity for a prolonged time, even after you start to feel tired. Those who ran <15km and 15-21 km had a respective decline in pace of 10.3% and 12.1%. In comparison, the >21 km long run group only slowed down by 9.4%.

Importantly, the longest long run in half marathon training is not the sole factor in determining performance. The same study reported a correlation between training volume and finish time. Additionally, training intensity (including any long run workouts) will also affect finish time.

Still, your longest run in half marathon training does contribute to race performance.

Long Run Distances to Run Before a Half Marathon, by Fitness Level

The longest run before a half marathon will differ based on your training background and current fitness. A first-time half marathon runner will approach their training very differently than a seasoned half marathoner.

In short: how far should you run before a half marathon?

• Novice: 10-11 miles (16-17 km)
• First-time half marathoner (but with a base): 12-13 miles (19-21 km)
• Intermediate: 13-14 miles (21-23 km)
• Experienced: 14-16 miles (23-26 km)

Here’s a closer look at how to think about your longest training run for a half marathon.

Novice runners: 10-11 miles (16-17 km)

A novice runner (someone with less than a year of running or who has never run long distances) will want to carefully build their long run distance over 14-16 weeks. Gradually building up long run distance is a priority over the longest long run, since the athlete will be adapting their metabolic system, musculoskeletal system, and mindset to the demands of long runs. If you have run no more than 6 miles ever, you may gradually build up to the longest run of 10-11 miles (16-17 km) in training over those weeks. They may frequently repeat weeks at a certain distance before adding another mile.

(That all said, I have coached individual novices to 13 miles before their race – but that was under close coaching supervision.)

Intermediate runners: 12-13 miles (19-21 km)

If you have been running for a few years before your first half marathon, you may be able to do a longer long run during training. For example, a runner who can complete 8 miles (12-13 km) comfortably before they start training for their first half marathon may be able to reach 12-13 miles (19-21 km) in training before race day.

Experienced runners: 14-16 miles (23-26 km)

Experienced runners who have completed half marathons before are better adapted to progress their long runs. These athletes are adapted to the biomechanical and metabolic demands of long runs. As a result, they can run over race distance in training. The practice of long runs longer than the half marathon (long runs lasting 14-16 miles) improves fatigue resistance and endurance.

Overdistance considerations

The frequency and exact distance of over-distance long runs depend on the athlete. An intermediate runner aiming for a 2 hour marathon may do one 14-mile long (23 km) run in training. An experienced 1:30 half marathoner may do multiple 14-16 mile (23-26 km) runs, plus long run workouts.

How to Run Farther in Half Marathon Training

If you struggle with long runs in half marathon training, you are not alone!

• Slow down: If you finish long runs feeling as if you cannot go another step, you may be running them too fast. Slow down! You cannot go too easy on long runs. If it helps, take walk breaks (while keeping your GPS recording). How slow should long runs be? Easy enough to chat with running buddies – or 1.5-3 minutes per mile slower than your goal pace.
• Fuel enough: If you feel like you are dragging through long runs, or you spend the rest of the day on the sofa, you may be underfueling. I have seen so many athletes not fuel on half marathon long runs only because they think it’s just for marathon training! In reality, intra-run nutrition should be used on any run longer than 80-90 minutes. For most half marathon training long runs, you want about 40-60 grams of carbohydrates per hour. If you will be on your feet for 2.5+ hours, then you may want to try as high as 90 grams of carbs per hour. You can use gels, chews, whole foods, sports drinks, or a combination of these carb-rich sport nutrition options. Start fueling early and often, such as every 30 minutes during the run. (Learn more about how to fuel your long runs in this article.)
• Hydrate: Dehydration does not enhance training adaptations! You will not become a mentally stronger runner by thickening your blood, stressing your nervous system, and overtaxing your body. Bring fluids with electrolytes on your half marathon long runs and drink appropriately for your sweat rate. If you struggle with hydration, consider doing a sweat test.
• Listen to an audiobook: Getting lost in a good story can help you run longer without getting bored. If you love novelty, use long runs to listen to new audiobooks. Or, if you are a comfort reader, revisit your favorites during your long runs.

You may also like: How to Feel Good on Your Long Runs

More Advice on Half Marathon Training

How Many Miles per Week for a Half Marathon?

A related question to figuring out how far to run before a half marathon race is how many cumulative miles you should aim to run in a given week. There are several factors to consider when answering this question, including your individual variations and how long you’ve been training.

» Read my full article on weekly mileage for half marathon runners here

How Long Should I Train for a Half Marathon?

Many online half marathon training plans range from 8 weeks to 20 weeks when preparing for a half marathon — which makes it tricky to plan for what is right for you.

As with determining the length of your longest training run before a half marathon, how many weeks you individually need to prepare for the race depends on goals, training experience, and current fitness.

Bonus: How Far Should You Run Before a Marathon?

A previous version of this article answers how far you should run before a marathon. Now, you can find more in-depth answers in these articles on how far you should run before a marathon and if you should limit long runs to three hours.

Run Your Best Half Marathon Yet

Want to work with a running coach for your next half marathon? Learn more about my coaching services here and schedule your initial consultation today!

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