Half Marathon Distance: 13.1 Miles / 21.1 KM Exact (2026)

Half a marathon distance is exactly 21.0975 km (13.1094 miles). Official conversion, pace tables, training links, and where to find half marathon races.

· 8 min read · Training

A half marathon is 21.0975 kilometres, or 13.1094 miles. Most race websites round that to 21.1K or 13.1 miles, which is close enough for training and pacing.

If you searched half a marathon distance or how many miles is a half marathon, the short answer is 13.1 miles / 21.1 km. If you are new to the distance, the half sits in a sweet spot: long enough to feel like a real endurance event, but short enough to recover within a week or two if you train sensibly.

| Fact | Figure | | --- | --- | | Exact distance | 21.0975 km / 13.1094 miles | | Common rounding | 21.1 km / 13.1 miles | | Metres | 21,097.5 m | | Typical finish | 1:45 to 2:30 |

Browse half marathon races once you have a date in mind, or start a half marathon training plan if the distance is still a few months away.

Half marathon distance in km and miles

| Unit | Exact | Common rounding | | --- | --- | --- | | Kilometres | 21.0975 km | 21.1 km | | Miles | 13.1094 mi | 13.1 miles | | Metres | 21,097.5 m | 21,100 m | | Yards | 23,074.7 yd | - |

How half marathon pace translates to finish time

| Finish time | Pace per km | Pace per mile | | --- | --- | --- | | 1:30 | 4:16/km | 6:52/mi | | 1:45 | 4:58/km | 8:00/mi | | 2:00 | 5:41/km | 9:09/mi | | 2:15 | 6:24/km | 10:18/mi | | 2:30 | 7:06/km | 11:27/mi |

For a full half marathon pace chart from 1:15 to 3:00, see our pace chart guide. Use the half marathon pace calculator if you want checkpoint splits for a specific goal.

Training for your first or next half

A structured build matters more than squeezing in random long runs. Start with a half marathon training plan for beginners that adapts to your current mileage and available days.

If you are still building from shorter distances, the 5K planner or Couch to 5K plan can be a better entry point before jumping to 21.1K.

Compare your target against average half marathon time by age and what counts as a good half marathon time before you lock a race-day goal.

Find races: Browse half marathon races worldwide, or narrow by city:

Pair race discovery with weekly parkrun consistency through our parkrun directory if you want a low-pressure Saturday benchmark during your build.

Half marathon vs full marathon distance

| Race | Exact distance | Common shorthand | | --- | --- | --- | | 5K | 5.000 km / 3.10686 mi | 5K / 3.1 | | Half marathon | 21.0975 km / 13.1094 mi | 21.1K / 13.1 | | Marathon | 42.195 km / 26.2188 mi | 42.2K / 26.2 |

A 5K is 3.10686 miles / 5.000 km. Full conversion: how many miles is a 5K. A half is exactly half of the marathon standard. That is why pacing tables scale cleanly: a 2:00 half and a 4:00 marathon share the same 5:41/km even pace on a flat course (though marathon fatigue means most runners cannot hold half pace for the full 42.2 km without specific training).

For the full distance in km, miles, and metres, see how long is a marathon.

Half marathon distance FAQs

How many miles is a half marathon?

13.1094 miles, usually rounded to 13.1 miles.

How long is a half marathon in km?

21.0975 km, usually rounded to 21.1 km.

What is half a marathon distance in km?

21.0975 km - the same official half marathon distance used worldwide.

How many metres is a half marathon?

21,097.5 metres. That is exactly half of the marathon's 42,195 metres.

Is a half marathon the same as 21K?

Almost. Officially it is 21.0975 km, so 21K is a slight underestimate.

How long does it take to run a half marathon?

Most recreational finishers land between 1:45 and 2:30, depending on experience and course profile. See average half marathon time for age-group context, then set splits with the half marathon pace chart.