How Long Is a Marathon? The 26.2-Mile Distance Explained

How Long Is a Marathon? The 26.2-Mile Distance Explained

Updated November 1, 2026 • U.S. English • Editorial draft

A full marathon is exactly 42.195 kilometers, which equals 26 miles and 385 yards, or 26.21875 miles. That is why it is routinely described as a 26.2-mile race: 26.2 is the rounded everyday label, while the full official distance is slightly longer.

Marathon distance conversion table

A kilometer contains 1,000 meters. A mile contains 1,760 yards, so the extra 385 yards beyond 26 miles equal 385 ÷ 1,760 = 0.21875 miles. The difference between the official 26.21875 miles and the simplified 26.2-mile label is about 30.2 meters.

Why is the marathon 26.2 miles instead of 26 miles?

The marathon grew out of early long-distance events that did not all use one identical route length. The now-standard 42.195-km distance became established after the London Olympic marathon of 1908 helped make a particular race distance well known. Modern regulated races use 42.195 km rather than allowing each organizer to decide that “about 26 miles” is enough.

This history also explains why miles and kilometers look awkward side by side: the standard was not chosen to create a round metric number. For participants, however, the unit conversion is straightforward and race organizers measure the course to the regulation distance.

Full marathon vs. half marathon vs. 10K

A half marathon is exactly 21.0975 km, or approximately 13.1094 miles. Doubling that metric distance gives the full 42.195 km. A 10K is 10 kilometers, so a marathon is 4.2195 times a 10K in distance. The training demands do not scale so neatly: maintaining a race pace for four times the distance brings much more fatigue and logistical planning.

The number of miles shown on a tracking watch may differ from 26.21875. Runners often take a wider line through turns, weave around other runners, or record small GPS errors near buildings. The race’s certified course distance is not a promise that every individual’s GPS trace will show the exact same number.

How long does it take to run 26.2 miles?

Distance and elapsed time are different questions. A runner averaging 9:09 per mile needs about four hours to cover the full marathon. Someone running at 11:27 per mile takes approximately five hours. Weather, hills, stops and fatigue can change those times, and the event’s allowed finish window is set separately by the organizer.

At road races, some splits display kilometers while others display miles. Runners who use min/km pacing should plan for 42.195 kilometers, not just 42 flat. A simple method is to know your target halfway split and compare it with later checkpoints rather than relying solely on instantaneous GPS pace.

What runners should remember about the final stretch

A race may display a Mile 26 marker even though the finish is still about 385 yards beyond that marker on a precisely marked course. That last stretch can feel much longer after hours of effort, but it is a normal consequence of the standardized distance. Do not assume the finish line will be exactly at a simplified “26.2” watch reading.

If you're preparing for your first full marathon, the next useful question is whether your training supports the distance and the time you hope to run. See Average Marathon Finish Time for time-goal examples, and How Many Miles Is a Half Marathon? for the shorter regulated race.

Frequently asked questions

Is a marathon 26.2 miles exactly?

No. It is exactly 26 miles and 385 yards (26.21875 miles). “26.2” is a rounded abbreviation.

How many kilometers are in a marathon?

Exactly 42.195 kilometers, or 42,195 meters.

Is a marathon exactly twice a half marathon?

Yes. The standardized half marathon is 21.0975 km, half of 42.195 km.

Why did my running watch say 26.4 miles?

Your chosen line through the course and GPS variation can increase the tracked distance; it does not automatically mean the official course was too long.