Signing up to train for and race a half marathon run is a big commitment. For runners ready to start a training program to prepare them to race 13.1 miles (21 kilometers), it's natural to wonder how much mileage will be required.

Of course, there's no one-size-fits-all answer when it comes to the ideal weekly mileage for a half marathon. Your personal best mileage will depend on several factors, including your experience and goals.

In this article, we'll touch on several considerations that you should take into account when determining your weekly mileage, including:

• How many days per week a runner should plan to train when preparing for a half marathon
• The factors you should consider when deciding how much to run
• The importance of gradual increases in mileage
• How to find your training and racing paces
• How to calculate the number of miles per week to run if your training plan is based on running time

Typical Training Loads for Half Marathoners

If you survey ten different half marathon runners about their weekly mileage or time spent training for a half marathon, you will likely get ten different answers. Most long-term runners spend years attempting to find their sweet spot for running mileage, meaning they seek to find a volume of training that is enough to allow for improvement but not so much as to lead to overuse injuries or burnout.

The Professionals: High Mileage Half Marathon Training

On one end of the spectrum of half marathon training volume, professional or elite runners may run up to or more than 100 miles a week as they prepare for endurance races, including 5k and 10k, half marathons, marathons, and beyond. Most of these runners train six or seven days a week, often multiple times a day. However, these higher mileage marathoners and other runners have lots of experience and have gradually increased their training volume over years. Many have also designed their lives to maximize their training and speed.

Amateur Runners: Reasonable Mileage the Fits Around Life

As a rule, we do not suggest that amateur runners follow similar high-mileage training schedules. Most amateur athletes have busy lives with major priorities like jobs and families. Half marathon training needs to fit around those priorities, while also allowing the runner time to recover. Similarly, newer age group runners need time to increase their endurance and durability.

Generally, we do not suggest that amateur runners run every day. The smarter approach is to run four to five days a week while also incorporating strength training and mobility work to keep the body strong and healthy.

The half marathon run training plans on the MOTTIV training app have been written by Olympians and world-class coaches at Run Free Training. For a half marathon race, our plans top out at a maximum of four runs per week, along with one mobility workout and one strength workout.

Within those four days of running per week, it's important to incorporate the right type of training sessions. Long runs are the cornerstone of any half marathon or marathon training program. Once you have a solid base of running, interval runs and tempo runs are also very useful. Additionally, slower recovery runs will help you build mileage and durability without adding risk of injury.

The half marathon training plans in our app are designed to fit around busy schedules and will prepare you to run your fastest without having to sacrifice the other important things in your life.

What Factors Affect How Many Miles I Should Run?

Because every runner is different, there is no definitive answer for how many weekly miles you should run to prepare for a half marathon. There are a few factors that should be taken into account in determining how much you should run.

Current Fitness

One of the most important running rules, particularly for new runners, is to start with low mileage and build volume gradually.

While running is one of the most fun forms of exercise, it's also one of the most likely to lead to injury. Because running is a weight-bearing activity, it is tough on your body's bones, muscles, and connective tissues. Studies have estimated that 20 to 80 percent of runners will experience lower-limb injuries in a year. And the factors that have been shown to increase the risk of injury:

• Running more miles than your body is ready for
• Running too many fast miles
• Previous injury history
• Being a novice runner

In light of these factors, your goal mileage for a half marathon will depend largely on how much running you have done recently.

If you're starting from scratch, start at a low running volume that you know your body can handle, such as two runs per week of just 30 minutes. Then, take a conservative approach to ramping up your mileage: build up the amount you run each week by no more than 8-10%.

Injury History

One of the best predictors of running injury is previous injury. In other words, if you've experienced knee pain in the past, you're more likely to experience knee pain again if you're not careful with your running mileage.

If you have had leg injuries related to sports in the past, it's wise to start with very low mileage, build your weekly running time very carefully, and always err on the side of running less rather than more.

Running Experience Level

An experienced runner who has, by trial and error, determined how much mileage their body can reasonably handle can usually build their running mileage to a higher weekly amount. Not only have these experienced runners logged the miles that make them durable, but they are also familiar with their bodies and know the warning signs that they may be doing too much. They've likely spent several training cycles learning their optimal mileage and intensity and can safely aim for more volume than a runner who is just getting started.

Half Marathon Race Goals

Your goals for the half marathon race will also affect your target running miles. For example, below are some sample training weeks for athletes who use our app and just want to finish a half marathon, athletes who want to finish the half marathon feeling strong, and athletes who want to compete:

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Assuming they are starting with general good fitness, most runners can safely complete the half marathon distance with three to four days of running per week. If your goal is merely to cross the finish line, running three days a week, entirely at an easy pace and with one long run, should be enough.

If you want to push your limits and run hard for the entire half marathon or race for a top finish, you'll want to build to four to six runs per week, plus strength training and mobility workouts, and time permitting, cross training.

A Note for Athletes From Other Sports

Even elite-level athletes coming to running from other non-weight-bearing sports, like swimming, still need to start with low mileage and build very slowly.

While a top-level athlete will quickly adapt to the cardiovascular demands of running, their musculoskeletal system (or their joints, tendons, and ligaments) will take months and even years of training to build up durability to withstand the pounding of running. In other words, the body needs time to catch up to the strong engine.

So, even if you are very fit and accustomed to large training volumes, be careful adding running miles to your routine.

How Many Miles Do Half Marathon Training Plans Call For?

Many running coaches, including those who have designed our training plans in the MOTTIV training app, prescribe training plans based on time rather than mileage, so it isn't easy to set a specific mileage goal for half marathon runners.

However, if you want to get a sense of how many miles per week you should expect to run when completing one of the half marathon training plans available on our app, you can refer to a couple of our calculators to get a ballpark figure.

Finding Your Training and Race Paces

First, use our pace calculator to get a sense of your goal half marathon time:

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For example, if your goal half marathon time is 2 hours, your goal marathon pace is 9:09 per mile (or 5:41 per kilometer).

This calculator will also tell you equivalent paces for the 5k and 10k distances. In this example, the equivalent 5k pace is 8:29/mile (5:16/ kilometer). The equivalent 10k pace is 8:48 / mile (5:28/ kilometer).

Then, use a couple of very general rules of thumb to determine typical run training paces:

• Your long and easy runs should be at least 60 to 90 seconds per mile slower than your half marathon pace.
• Your moderate tempo runs should be around your half marathon pace or a little faster.
• Your interval run paces should be about your 5k pace or a bit quicker.

For our 2-hour marathoner, that would mean rough training paces would be around:

• Long/easy runs: around 10:30 / mile
• Tempo runs: around 9:00/ mile
• Interval runs: around 8:30 / mile

Finding the Number of Hours To Train Per Week

Next, you can use this calculator to determine how many hours per week to train based on your half marathon goals and your athletic background:

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Based on this calculator, here are the hourly training goals per week for a few example types of runners:

• A runner with no running background whose goal is to finish: 3 to 5 hours of running per week
• A runner with a modest running background whose goal is to finish strong: 5 to 6 hours of running per week
• A runner with an elite sports background whose goal is to compete for a top finish: 6 to 7 hours of running per week

Calculating Weekly Mileage

After determining your general training paces and the hours per week of running that you should aim to achieve, we can calculate the weekly mileage to expect while training for a half marathon. This takes a few steps.

Most importantly, remember that about 80% of your training time should be spent on easy running, while about 20% of the time you spend running should be fast running.

With that in mind, follow these steps:

1. Using the calculators above, determine how many hours per week will be devoted to easy running and how many to fast running.

For example, assume you are a moderately experienced runner whose goal is to finish the half marathon with a strong time of 2 hours. The calculator told you to aim for 5 hours per week of running. That's 300 minutes (5 hours x 60 minutes).

80% of the 300 weekly minutes (or 240 minutes, which is 4 hours) should be devoted to easy running. 20% of your weekly running time (about 60 minutes) should be devoted to fast running.

1. Using your training paces, calculate how many easy and fast miles or kilometers you'll cover in that allotted weekly time.

Using our training paces calculator, for our 2-hour 10k runner, easy runs should be done at around 10:30 per mile or about 6:15 per kilometer. At a 10:30 mile, our runner will cover about 23 miles of easy running per week (240 minutes total divided by 10.5 minutes per mile). That equals about 49 kilometers.

Similarly, if our 60-minute 10k runner runs about 9:00/ mile, or 5:30/ kilometer for her fast pace, she'll cover about 7 miles of fast running per week (60 minutes divided by 9 minutes per mile). That equals about 11 kilometers.

1. Add the easy and fast running miles for your anticipated weekly mileage.

In this case, our runner can expect to run 30 miles per week (23 miles easy plus 7 miles fast) or 40 kilometers per week (38 kilometers easy plus 11 kilometers fast).

Examples of Weekly Mileage for Different Runners

Using the steps outlined above, here are a couple of charts that show anticipated weekly mileage for various runners of different speeds with different goals for weekly miles:

MILES

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Kilometers

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Remember, these calculations represent the most weekly mileage that you'll likely run in your build-up to a half marathon and are mere suggestions that should be altered based on your circumstances. As always, start slow and build your mileage gradually.

Wrap-Up

Every runner is different when it comes to weekly mileage. While we can provide general guidelines for how many hours per week to run to prepare for a half marathon, the actual mileage may depend on several factors, including your background, goals, injury history, and speed.

In this article, we've addressed:

• How frequently to expect to run when training for a half marathon
• The importance of starting with low mileage and building your running volume gradually
• The factors that influence how many miles you should run per week
• Tips for calculating expected weekly mileage

While many runners track their weekly mileage, the best approach is to listen to your body and only do as much as you know your body can handle. Building your mileage gradually and cautiously makes you much more likely to avoid injury and enjoy training for your half marathon.