How Many Miles a Week Should You Run? By Race Distance and Finish Time

How Many Miles a Week Should You Run for Each Race Distance?

Our reference points for a peak week are 15 to 25 km (9 to 16 miles) to finish a 5K, 20 to 30 km for a 10K, 25 to 40 km for a half marathon and 40 to 65 km for a marathon. These are weekly running mileage reference points, and you reach them step by step. They are not where you start.

Here are the ranges for the peak week of a build, in kilometers with miles in brackets. Each distance has three levels: finish (get to the line in good shape), improve (run faster than last time) and perform (race for a specific time).

• 5K: finish 15 to 25 km (9 to 16 miles), improve 25 to 40 km (16 to 25 miles), perform 40 to 60 km (25 to 37 miles).
• 10K: finish 20 to 30 km (12 to 19 miles), improve 30 to 50 km (19 to 31 miles), perform 50 to 70 km (31 to 43 miles).
• Half marathon: finish 25 to 40 km (16 to 25 miles), improve 40 to 60 km (25 to 37 miles), perform 60 to 80 km (37 to 50 miles).
• Marathon: finish 40 to 65 km (25 to 40 miles), improve 60 to 85 km (37 to 53 miles), perform 85 to 115 km (53 to 71 miles).

At TrainingZones.io, we built these ranges from published training plans. They are reference points, not predictions, and nobody should treat them as a rule that fits every body. Notice the word peak: a week like that is the top of a build, not what every week looks like.

Pick your distance and your level in the calculator below and it shows your range, plus how far your current weekly distance sits from it. You can also open the full Weekly Mileage Calculator on its own page.

What Do Marathon Runners Really Run Each Week, by Finish Time?

In a study of 151,813 marathons, runners who finished between 3:30 and 4:00 averaged 48 km (30 miles) a week in their busiest month, against 76 km (47 miles) for 2:30 to 3:00 and 36 km (22 miles) for 5:00 to 5:30. Those are monthly averages, not peak weeks.

The data come from Muniz-Pumares et al. (2025), who looked at 119,452 runners and the 16 weeks before each race, using training logs. The explorer below shows the nine finish-time bands. Select one to see the four months before the race and the number of days a week with a run.

Here is the busiest month of each band, with the average number of days with a run in that month:

• 2:00 to 2:30: 120 km (75 miles) a week, 5.7 days with a run (620 marathons).
• 2:30 to 3:00: 76 km (47 miles), 4.6 days (14,608 marathons).
• 3:00 to 3:30: 57 km (35 miles), 3.8 days (37,307 marathons).
• 3:30 to 4:00: 48 km (30 miles), 3.4 days (43,764 marathons).
• 4:00 to 4:30: 43 km (27 miles), 3.2 days (27,263 marathons).
• 4:30 to 5:00: 39 km (24 miles), 3.1 days (14,879 marathons).
• 5:00 to 5:30: 36 km (22 miles), 3.0 days (6,223 marathons).
• 5:30 to 6:00: 34 km (21 miles), 2.9 days (2,503 marathons).
• 6:00 to 6:30: 32 km (20 miles), 2.9 days (845 marathons).

Look at the days too. Runners finishing between 3:30 and 4:00 had 3.4 days with a run in their busiest month, those at 2:30 to 3:00 had 4.6 and the 2:00 to 2:30 band had 5.7. Volume rises with both the number of days and the length of the runs, and these data cannot say which of the two matters more.

Three things stand out. First, the busiest month was the one two months before the race in every band, and the last month was lighter, which is consistent with a taper. Second, most of the runners sit in the middle: roughly 7 in 10 of the marathons in the nine bands were finished between 3:00 and 4:30.

Third, and this is the part people get wrong, this table runs in one direction only. It tells you the average volume of people who finished in a given time. It does not tell you what time you will run on a given volume. Someone logging 48 km a week is not "a 3:45 marathoner": they may be faster or slower, and the data cannot say.

Does a Higher Weekly Mileage Make You Faster in a Half Marathon?

In a survey of 556 half marathon runners, those who trained over 32 km a week finished in 1:55:26 on average, against 2:02:03 for 20 to 32 km and 2:05:32 for under 20 km. After adjustment, the group over 32 km was about 4 minutes faster than the 20 to 32 km group (4.19 minutes). The distances were reported by the runners themselves.

That comes from Fokkema et al. (2020), who asked half marathon and marathon runners about their training. The three half marathon groups had 129 runners (under 20 km), 233 runners (20 to 32 km) and 193 runners (over 32 km). The raw gap between the under 20 km group and the over 32 km group is about 10 minutes, and it is tempting to read it as "more kilometers equals 10 minutes".

Be careful with that reading. This is a survey, so it shows an association, not a cause. Runners who train more may also have more experience, more talent or a coach, and the study cannot separate those from the kilometers.

The adjustment helps: between the 20 to 32 km group and the over 32 km group, the raw gap is 6 minutes 37 seconds (2:02:03 against 1:55:26), and it shrinks to about 4 minutes after adjustment.

The same study has a marathon part with 441 runners. Averages were 4:31:03 under 40 km a week, 4:19:04 between 40 and 65 km and 3:43:03 over 65 km. The top group had only 43 runners, so treat that last number as a rough picture rather than a benchmark.

Why Do Websites Disagree on Weekly Running Mileage?

Websites disagree because they mix different things under one word. Some report what runners do, others what coaches advise. Some give a monthly average, others a peak week. Some use miles, others kilometers, and some talk about level while others talk about finish time.

Four reasons explain most of the gaps:

• Measured versus advised. The marathon table above is a measurement of what runners did. A published plan is advice about what to do, and plans often ask for more.
• Monthly average versus peak week. The 57 km measured for 3:00 to 3:30 is an average over a month. A plan lists the biggest week, which is higher, so the two cannot be compared directly.
• Miles versus kilometers. Runner's World gives 30 to 60 miles for a marathon, which is 48 to 97 km. A page that quotes such numbers without naming the unit can be off by a factor of 1.6.
• Level versus finish time. For the 5K and 10K, pages talk about levels. For the marathon, they talk about finish times.

A few terms help keep the vocabulary straight:

• Peak week: the biggest week of a build, the number most plans and our ranges refer to.
• Monthly average: the mean weekly distance over a whole month, which is never higher than the biggest week of that month.
• Self-reported: the runner typed or recalled the number, so it can be off.
• Easy running (zone 1): the relaxed part of training, where you could hold a conversation.

The 5K shows the problem well. Runner's World gives 10 to 25 miles (16 to 40 km), and Strongerlab gives 20 to 40 km for an ambitious 5K. Both can be right: they answer different questions, finishing versus improving.

What Weekly Mileage for a 5K or a 10K?

Unlike the marathon, we found no measured dataset for the 5K or the 10K that we could read. So for these two distances, everything below is published advice, attributed to its source, not a measurement of what runners do.

Here is what the pages we read say:

• Runner's World: 10 to 25 miles (16 to 40 km) for a 5K and 25 to 30 miles (40 to 48 km) for a 10K.
• Marathon Handbook: 15 to 25 miles (24 to 40 km) for a 5K and 20 to 30 miles (32 to 48 km) for a 10K, for average runners.
• Strongerlab: 20 to 40 km for an ambitious 5K and 30 to 50 km for an ambitious 10K.

Our ranges fall inside this spread: 15 to 60 km for the 5K and 20 to 70 km for the 10K, depending on whether you want to finish, improve or perform. The honest answer is that a 10K finisher and a 10K racer need very different weeks.

One more point. At TrainingZones.io, the calculator shows only the advised range for the 5K and 10K, and says so, because there is no measurement to show. For the half marathon and marathon, it adds what the studies measured.

What Long Run Should You Do for Your Weekly Mileage?

In the Fokkema et al. (2020) data, half marathon runners whose longest run was over 21 km finished in 1:51:31 on average, against 2:03:28 for 15 to 21 km and 2:06:48 for under 15 km. After adjustment, the over 21 km group was 3.87 minutes faster than the 15 to 21 km group.

For the marathon, the same study found averages of 4:37:43 for a longest run under 25 km, 4:25:07 for 25 to 30 km, 4:15:26 for 30 to 35 km and 3:50:18 for over 35 km.

One result deserves attention: after adjustment, the difference for the over-35 km group compared with 30 to 35 km was not statistically significant. In plain terms, the study could not show that going past 35 km makes a difference once other factors are accounted for.

So what do the published plans do? Hal Higdon's Novice 1 half marathon plan runs 12 weeks, with a long run that grows from 3 to 10 miles, and its busiest week adds up to 23 miles (37 km, our own sum from the published schedule).

His Novice 1 marathon plan has a peak week of 5, 10, 5 and 20 miles, 40 miles in total (64 km, our sum), so the long run is half of that week.

His Advanced 1 marathon plan peaks at 50 miles or more with a 20 mile long run (our sum, speed work not counted), so there the long run is a smaller share. The point: the long run does not grow in proportion to the week. In these plans, the extra volume comes from the other runs.

Does Running More Kilometers Work at Every Level?

More kilometers are associated with faster marathons, but the link is not proven to be a cause and it flattens as volume goes up. Tanda (2011) found a relationship between weekly distance and marathon pace in 22 runners finishing between 2:47 and 3:36. It cannot be applied outside that group.

The formula is: marathon pace (seconds per kilometer) = 17.1 + 140 × e^(-0.0053 × K) + 0.55 × P. Here K is the weekly distance in kilometers and P is the average training pace in seconds per kilometer, both over 8 weeks. The exponential term gets smaller as K grows, but each extra kilometer lowers it less than the previous one, which is the diminishing return people feel in practice.

Do not use this formula if your marathon is outside 2:47 to 3:36. That is where it was fitted, and nowhere else is it supported. Our calculator applies the same limit and shows no result for anyone outside it.

Now the part that cools the enthusiasm. Muniz-Pumares et al. (2025) looked at training intensity across performance levels in the same marathon data. Faster groups ran more, but most of the extra volume was easy running in zone 1, while the time spent in zones 2 and 3 stayed roughly flat between groups.

That matches the way many coaches build volume: more easy running, not more hard running. It is also likely that talent and training history explain part of the gap between groups. The data cannot tell you how many minutes an extra 10 km would buy you.

How to Go From Your Current Mileage to Your Race Goal

To go from your current mileage to your race goal, compare your real weekly distance with the range for your distance and level, then close the gap gradually over the weeks of your plan. Most of what you add should be easy running.

1. Write down your current weekly distance, as an average of the weeks you actually ran, not your best week.
2. Choose your distance and your level (finish, improve or perform) and read the range for your peak week in the Weekly Mileage Calculator.
3. Compare the two numbers. If you are below the bottom of the range, the difference is what you build over the whole plan. If you are inside the range, you already have the volume.
4. Spread the build across the weeks, not in a few jumps. A common rule of thumb is to add about 10 percent a week at most, and it is only a guideline.
5. Put most of the added distance into easy running. In the marathon data, the extra volume of faster groups was mostly zone 1.
6. Plan lighter weeks inside the build and a lighter last month, as the measured runners did, then recheck your numbers.

What if you are already above the range? Then the calculator marks it as above, and that is not a problem in itself. It means your goal does not call for more volume, and the question becomes how you spread the week and where the intensity goes.

Your target pace matters too. Work it out with the Race Predictor or the VDOT Calculator, then set race-day pacing with the Race Pace Calculator. To track how the weeks add up, the Training Load Calculator turns your sessions into a load number.

Our pick: The Garmin Forerunner 265 records each of your runs, so you can track your weekly volume through a build like this one.

With TrainingZones.io, you get the calculators above in one place, and the reasoning behind each number is in the guides.

Frequently Asked Questions About Weekly Running Mileage

Is running 25 miles a week a lot?

It depends on where you come from. 25 miles is about 40 km, which is the top of our half marathon finish range (25 to 40 km) and the bottom of the improve range (40 to 60 km). It is a lot if you were at 10 miles last month, and ordinary if you have built up to it over time.

Is 20 miles a week of running good?

Yes, for many goals. 20 miles is about 32 km, which falls inside the 10K improve range (30 to 50 km) and the half marathon finish range (25 to 40 km). It is a good base for those distances when you reach it gradually.

Is running 20 miles a week too much?

There is no universal answer: the jump matters more than the number. If you ran 8 miles a week last month and go straight to 20, that is a big change. If you got there over several months, it sits within the usual ranges for a 10K or half marathon. If something hurts persistently, see a health professional.

What is a good weekly mileage for a marathon?

For the peak week, our ranges are 40 to 65 km to finish, 60 to 85 km to improve and 85 to 115 km to perform. In the marathon study, the busiest-month averages by finish-time group range from 32 km (6:00 to 6:30 finishers) to 120 km (2:00 to 2:30 finishers), so the answer depends on your goal. You can check your own numbers on TrainingZones.io.

Should I run 10 miles a week before my half marathon?

10 miles is about 16 km, which is a reasonable starting point for a first half marathon. Runner's World Germany gives 15 to 25 km for beginners, and Campus Coach starts at 15 to 20 km. It is below the 25 km bottom of our finish range for a peak week, so you would build from there.

Is 40 miles a week enough for marathon training?

40 miles is about 64 km, which is near the top of our marathon finish range (40 to 65 km) and above the 48 km busiest-month average of the 3:30 to 4:00 band. In Fokkema et al., the 40 to 65 km group averaged 4:19:04. An average is not a promise, but it is a workable volume for finishing.

References

• Muniz-Pumares D, Hunter B, Meyler S, Maunder E, Smyth B (2025). The training intensity distribution of marathon runners across performance levels. Sports Medicine, 55(4):1023-1035. DOI 10.1007/s40279-024-02137-7.
• Fokkema T, van Damme AADN, Fornerod MWJ, de Vos RJ, Bierma-Zeinstra SMA, van Middelkoop M (2020). Training for a (half-)marathon: Training volume and longest endurance run related to performance and running injuries. Scandinavian Journal of Medicine and Science in Sports, 30(9):1692-1704. DOI 10.1111/sms.13725.
• Tanda G (2011). Prediction of marathon performance time on the basis of training indices. Journal of Human Sport and Exercise, 6(3):511-520. DOI 10.4100/jhse.2011.63.05.
• Higdon H. Novice 1 half marathon, Novice 1 marathon and Advanced 1 marathon training programs. halhigdon.com.