Why Is a Marathon 26.2 Miles?

The Short Answer

If you want just the numbers, here they are:

The “.2” is not a rounding error or an afterthought. It is a deliberate artifact of a specific course laid out through the English countryside to satisfy a very specific royal viewing arrangement. Read on for the full story.

The Legend of Pheidippides

Why is a marathon 26.2 miles? To answer that properly, you have to start with why the event exists at all—and that means Greece, 490 BC, and a story that may or may not be entirely true.

The legend goes like this: a Greek messenger named Pheidippides ran from the town of Marathon to Athens—roughly 25 miles (about 40 km)—to announce that the Athenian army had defeated the Persian invaders at the Battle of Marathon. He burst into the assembly, shouted something to the effect of “We have won,” and then collapsed and died.

It is a compelling story. It is also, by the standards of modern historical scholarship, a legend rather than firmly documented fact. The earliest surviving account comes from the Greek historian Herodotus, who wrote about Pheidippides running to Sparta before the battle—not to Athens after it. The famous post-battle run to Athens appears in texts written centuries later. The name, the exact route, the dramatic death: all of it belongs to the realm of tradition.

None of that makes the story less powerful. When Pierre de Coubertin and his colleagues revived the Olympic Games in 1896, they wanted an event that connected the modern Games to ancient Greece. A long-distance race from Marathon to Athens—the legendary route of Pheidippides—was the answer. The legend gave the race its name and its romance, even if history is fuzzy on the details.

The First Olympic Marathons Were ~40 km

The inaugural modern Olympic marathon, run in Athens in 1896, covered roughly 40 km—an approximation of the legendary route from the town of Marathon to the Panathenaic Stadium in Athens. Greek runner Spyridon Louis won in a time that would make most recreational runners wince with envy.

Here is what many runners do not know: for the next several Games, nobody agreed on how far a marathon should be. The distance was treated as “roughly 40 km” and varied course by course:

Runners competing across multiple early Olympics were essentially running different races each time. The 1904 St. Louis marathon was infamously chaotic for reasons beyond distance—dust, heat, cars on the course, a competitor who hitched a ride—but the inconsistency in distance was its own absurdity. Something had to give.

The 1908 London Olympics Set 26.2 Miles

The 1908 London Olympics is where the modern marathon distance was born, and it happened for a reason that is simultaneously mundane and very British: the royal family wanted a good view.

The course was planned to run from Windsor Castle to the finish line at White City Stadium in west London. The start was placed on the grounds of Windsor Castle specifically so that the royal children could watch the runners set off from the royal nursery window. The finish line was positioned in front of the royal box inside the stadium. When surveyors measured the resulting route, it came out to 26 miles 385 yards—42.195 km.

The 385 yards (approximately 352 meters) is the piece that trips people up. Why 385 yards? Because that is how far it was from the stadium entrance to the spot directly in front of the royal box. The in-stadium finish loop added those yards to the total. It was not calculated for any athletic or physiological reason. It was logistics shaped around aristocratic seating.

The race itself became one of the most famous in Olympic history for a different reason. An Italian runner named Dorando Pietri entered the stadium first but collapsed multiple times on the final lap. Officials helped him across the finish line—disqualifying him. American Johnny Hayes was awarded the gold medal. The controversy kept the 1908 marathon in the headlines for months and cemented the race, and its unusual distance, in public memory.

That distance—26 miles 385 yards—would not go away.

Standardized in 1921

After 1908, the marathon distance drifted again. The 1912 Stockholm course was approximately 40.2 km. The 1920 Antwerp course stretched to roughly 42.75 km. Runners, coaches, and national federations had no single number to train toward.

In 1921, the IAAF—the International Association of Athletics Federations, now called World Athletics—stepped in and fixed the marathon distance officially at 42.195 km. The chosen figure was the 1908 London course distance. The 1924 Paris Olympics were the first Games to use the standardized distance, and every Olympic marathon since has covered exactly 42.195 km.

Why 42.195 and not a round number like 40 km or 25 miles? Because the governing body chose to honor an existing precedent rather than invent a clean number. The 1908 London course had the most famous marathon in recent memory attached to it. The IAAF went with what was already famous.

The result is that every runner who crosses a marathon finish line today—whether in Berlin, Boston, or a small-town local race—is running a distance defined by where a group of royal children were standing on a lawn in Windsor in July 1908.

Frequently Asked Questions

Why is a marathon 26.2 miles?

A marathon is 26.2 miles because of the 1908 London Olympics. The course ran from Windsor Castle to the finish line in front of the royal box inside White City Stadium, measuring 26 miles 385 yards (42.195 km). The IAAF standardized this distance in 1921, and it has been the official marathon length ever since. There is no physiological rationale for the number—it is purely historical.

Where do the extra 385 yards come from?

The 385 yards come from the in-stadium finish at White City Stadium in 1908. After entering the stadium, runners had to complete a partial lap to reach the finish line, which was positioned directly in front of the royal box. That loop added approximately 385 yards (352 meters) to the 26-mile road course. Without the royal-box placement, the distance would have been different.

How long was the first Olympic marathon?

The first modern Olympic marathon, run in Athens in 1896, was approximately 40 km (about 24.85 miles). It followed a rough approximation of the legendary route from the town of Marathon to Athens. The distance was not precisely defined and varied between Games until the IAAF standardized it at 42.195 km in 1921.

Who was Pheidippides?

Pheidippides is the legendary Greek messenger said to have run from Marathon to Athens after the Battle of Marathon in 490 BC to announce the Greek victory over Persia, then died on the spot. This story, while widely repeated, is more legend than documented history—the historian Herodotus, our primary source for the battle, describes Pheidippides running to Sparta before the battle, not to Athens after it. The post-battle run appears in much later texts.

When was the marathon distance standardized?

The marathon distance was officially standardized at 42.195 km (26 miles 385 yards) in 1921 by the IAAF (now World Athletics). The 1924 Paris Olympics were the first Games to use this standardized distance. Before 1921, marathon courses varied from roughly 40 km to 42.75 km depending on the host city and course layout.

How many kilometers is a marathon?

A marathon is exactly 42.195 kilometers, which equals 26.2188 miles or 26 miles 385 yards. In casual usage, runners round this to 26.2 miles or 42.2 km. The precise figure—42.195—is the one fixed by the IAAF in 1921 and used for all official marathon races worldwide, including the Olympics, World Marathon Majors, and qualifying races.

Related Guides

• Marathon distance in miles—full breakdown
• Half marathon distance explained
• How long does it take to run a marathon?
• Pace calculator hub
• Marathon pace chart and splits
• AI run coach—personalized marathon training

Run Your Own 26.2

Now you know why a marathon is 26.2 miles: a course measured through the English countryside to give a royal family a good view, frozen into history by an Italian runner who could not quite make it across the finish line on his own. The number is arbitrary. The achievement is not.

If you are training for your first marathon or chasing a PR on your tenth, WattRun builds a personalized training plan around your current fitness—whether you are coming from a 5K base or recovering after a long break. Smart pacing, structured long runs, and AI coaching adapted to your data.

Train for your 26.2 with WattRun

Last updated: May 2026. Sources: International Olympic history; World Athletics standard distance (42.195 km, standardized 1921).