Race Distance Conversion Chart: 5K to Marathon in Miles and Km

A 5K is 3.1 miles, a 10K is 6.2 miles, a half marathon is 13.1 miles, and a full marathon is 26.2 miles. Those four numbers cover most of what runners need, but the world of road and trail racing runs from a 5K all the way up to a 100K ultramarathon, and every event is set in a metric distance that then gets translated for runners who think in miles. This page is the conversion chart that does the translating: one clean, scannable table showing every common race distance in kilometers, miles, meters, and approximate 400 meter track laps, plus the typical finish time you can expect.

Race directories and finish-line photo sites dominate searches for race distances, yet almost none of them publish an actual chart. Long explainer articles bury the numbers in paragraphs. The fix is simple. Below is the real table, followed by both conversion directions, typical times for every distance, and a free converter you can use for any number you like.

The complete race distance conversion chart

Here is the full ladder of common race distances, from a parkrun 5K up to a 100K ultramarathon. Each row shows the distance in kilometers, miles, and meters, plus roughly how many laps of a standard 400 meter outdoor track it would take. Track-lap figures are approximate, since most of these distances are run on roads or trails rather than a track.

The miles column rounds to two decimals so the conversion is precise, but in everyday running language a 5K is just "3.1" and a marathon is just "26.2". The 5K, 10K, half marathon, and full marathon are the four distances you will see on almost every race calendar, which is why we have dedicated deep-dive guides for each of them, linked further down this page.

Converting kilometers to miles

Race organizers around the world set distances in metric units because the metric figures are clean round numbers: 5, 10, 21.0975, and 42.195 kilometers. Runners in the United States then translate those numbers into miles. The conversion never changes, and it rests on one fixed ratio.

1 kilometer equals 0.621371 miles. To convert any kilometer distance into miles, multiply by 0.621371. A 10K becomes 10 multiplied by 0.621371, which is 6.21 miles. A 5K becomes 5 multiplied by 0.621371, which is 3.11 miles. The math is identical for every distance, so once you know the ratio you can convert any race in seconds.

Converting miles to kilometers

The reverse direction matters just as much, especially when a course in the United States is measured in miles and you want the metric equivalent for a training app or a foreign race.

1 mile equals 1.609344 kilometers. To convert miles into kilometers, multiply by 1.609344. A 10 mile race becomes 10 multiplied by 1.609344, which is 16.09 km. A 13.1 mile half marathon becomes 21.0975 km, and a 26.2 mile marathon becomes 42.195 km. Because 1 mile is a little over 1.6 km, every distance looks like a bigger number in kilometers, which is one reason the metric figures can feel more intimidating even though the run itself is identical.

Typical finish times for every race distance

Raw distances only tell half the story. Most runners also want to know how long an event will actually take. The table below gives realistic time windows for three broad ability levels: a new runner often using walk breaks, an average recreational runner, and a competitive club runner. These are honest ranges, not records, and terrain, weather, and elevation can shift any of them.

Notice that times do not scale in a perfectly straight line with distance. A 10K does not take exactly twice a 5K, because runners settle into a slightly slower sustainable pace as the distance grows. The drop in pace from a 5K to a marathon is the single biggest reason endurance training exists: holding a comfortable speed for 26.2 miles is a very different skill from racing hard for 3.1.

Use the converter for any distance

The chart covers every standard event, but training runs, trail races, and unofficial distances rarely land on a round number. The converter below handles any value you enter and works in both directions.

The four core distances explained

Most racing careers are built on the same four steps. Each one is a meaningful jump, and each has its own training rhythm. We keep this section short because each distance has a full dedicated guide, but here is the quick map of the ladder.

The 5K (3.1 miles) is the entry point to organized running. It is long enough to be a real fitness goal and short enough that a healthy but untrained adult can prepare for one in six to eight weeks. For the full breakdown of pacing, step counts, and walking times, see our guide on how many miles is a 5K.

The 10K (6.2 miles) is simply two 5Ks back to back, and it is the classic second goal once a 5K feels comfortable. It rewards a touch more endurance without demanding the long weekend runs that a half marathon needs. A dedicated 10K guide covers training plans and split tables for this distance.

The half marathon (13.1 miles) is a serious step up that most runners train for across 10 to 14 weeks. It is the most popular "big" race distance because it is genuinely challenging yet still recoverable within a few days.

The full marathon (26.2 miles) sits in a category of its own. The 42.195 km distance asks for several months of consistent mileage and careful pacing. Our dedicated marathon guide explains the training arc and the history behind the unusual 26.2 figure in detail.

Why the half and full marathon use odd numbers

Every distance on the chart is a clean metric figure except two: the half marathon at 21.0975 km and the full marathon at 42.195 km. Those numbers trace back to the 1908 London Olympics. The marathon course that year was set at 26 miles 385 yards so it could start at Windsor Castle and finish in front of the royal box at the stadium. That exact distance, 26 miles and 385 yards, converts to 42.195 km, and in 1921 the governing body of athletics adopted it as the permanent official standard.

The half marathon is defined as exactly half of that figure, which is why it carries the same long decimal. So the odd numbers are not a quirk of conversion at all. They are a deliberate, fixed standard, and the awkward decimals only appear because the original distance was set in miles and yards rather than kilometers.

Beyond the marathon: ultra distances

Anything longer than the 42.195 km marathon counts as an ultramarathon. The most common ultra distances are the 50K (31.07 miles), the 50 miler (80.47 km), the 100K (62.14 miles), and the 100 miler (160.93 km). The 50K is the gentlest introduction, because it is only about five miles longer than a marathon, which is why it appears on the main chart above as the first ultra step.

Many trail ultras ignore round numbers entirely. A mountain race is often measured by the loop or the route between aid stations, so you will see odd distances like a 43 mile or a 73 km event. When a race uses a number that is not on any standard chart, the converter above is the fastest way to picture it in whichever unit you think in.

A quick mental shortcut

If you ever need a rough conversion without a calculator, remember that 8 kilometers is very close to 5 miles. That ratio gives you a fast estimate: multiply kilometers by 5 and divide by 8 for an approximate mile figure, or multiply miles by 8 and divide by 5 to estimate kilometers. It is not exact, but for a 10K it gives 6.25 miles against the true 6.21, which is close enough to picture the distance. For anything that needs real precision, such as pacing a race or logging training, use the exact ratios and the converter on this page.