If you have decided to run a marathon, the first question worth answering is the simplest one. A marathon is 26.2 miles, or precisely 42.195 kilometers, which is 26 miles and 385 yards. That distance is fixed by World Athletics and has been the official marathon length at every major race in the world for more than a century.
Where the 26.2 came from
The number is the result of one specific design decision at the 1908 London Olympics. The British organizers wanted the race to start at Windsor Castle and finish in front of the royal box at the Olympic stadium in White City. The distance that gave them, measured along the planned route, was 26 miles and 385 yards. The race went off, the runners covered the distance, and when World Athletics formally standardized the marathon in 1921 they kept the London number rather than picking a round one.
That is why the marathon is not 26 miles, not 42 kilometers, and not any other clean number. It is an architectural decision from a single race in 1908 that the rest of the running world inherited.
How long does it take to run a marathon?
For most amateur runners, somewhere between three and five hours. A rough breakdown of typical finishing times:
- Sub-3 hours: serious, well-trained runners. About 4 to 5 percent of all finishers.
- 3:00 to 4:00: the strong amateur range. Solid weekly mileage, multiple marathons of experience.
- 4:00 to 5:00: the largest band of finishers. First-time and second-time marathoners, including most charity runners.
- 5:00 to 6:00: a healthy walk-jog-run pace. Many large-city marathons set a 6-hour cutoff at this band.
- 6:00 plus: finisher status, fully respectable, especially on hilly courses.
World records sit far on the other side of the curve. On April 26, 2026, Sebastian Sawe ran 1:59:30 at the London Marathon to become the first person to break the two-hour barrier in a race-legal marathon. The women's world record stands at 2:09:56, set by Ruth Chepngetich at the 2024 Chicago Marathon. For women-only events, Tigst Assefa holds the record at 2:15:41 from London 2026.
What does 26.2 miles actually feel like?
One way to anchor the distance in your head: a marathon is roughly the same as five back-to-back parkrun 5Ks, plus a parkrun's worth on top. It is about an hour of running for the world record pace, three to four hours for a fit amateur, and the better part of an afternoon for a first-timer.
On a treadmill at 6 mph (about 10 minutes per mile), a marathon takes 4 hours 22 minutes. At 8 mph (7:30 per mile), it takes 3 hours 17 minutes. At 10 mph (6:00 per mile), it takes 2 hours 37 minutes, which is faster than most well-trained amateur runners can sustain for that long.
Marathon vs other race distances
The marathon is the longest of the standard road race distances. For context:
- 5K: 3.1 miles or 5 km
- 10K: 6.2 miles or 10 km
- Half marathon: 13.1 miles or 21.0975 km, exactly half of a marathon
- Marathon: 26.2 miles or 42.195 km
- Ultramarathon: any race longer than a marathon. The most common ultra distances are 50K, 50 miles, 100K, and 100 miles.
The number is the same. The experience is not.
What changes from runner to runner is not the distance. It is how the body handles it. A 26.2 mile run on a flat, cool, well-supported course is a fundamentally different event from the same distance on a hilly course in 30°C heat, even though the number on the finisher medal is identical. This is why marathon training is not just about being able to cover the distance, but about being able to absorb it on the day.
That is also why training for a marathon takes months, not weeks. The aerobic, muscular, and skeletal adaptations that let your body handle three to five hours of continuous running take time to develop. There is no shortcut.
Ready to train for one?
If you have signed up for a marathon, you have already done the hardest part: committed. Now the question is how to fill the months between now and the start line. Smart Runner's first-marathon training plan takes the standard 16-to-20-week build and adapts it to your pace, your week, and your weather. Onboarding takes 5 minutes. The plan adapts every week from there.