How many miles is a 5K?

Updated August 26, 2026 · By the Runked team

Race distances get quoted in miles, kilometers and meters depending on the country and the source, which is exactly why the same race gets called "the 5K," "5km" and "3.1 miles" in the same sentence. Below is one reference table for the standard distances, sourced to World Athletics' own rules and event pages, verified today.

Race distances in miles, kilometers and meters

This table is Runked's own, built by applying World Athletics' own conversion for the Road Mile, 1 mile equals 1,609.344 meters exactly, to every standard distance listed in its Technical Rules. Miles are rounded to one decimal place, except where the metric and imperial distances are both round numbers by definition (1 mile, 10 miles), and except the 400m lap, shown to two decimals (0.25 mi) since that's the precision needed to compare it against an imperial quarter mile.

Why these are the standard distances

World Athletics' Technical Rules, 2026 edition, set the standard road-race distances directly; the same document is listed on World Athletics' Book of Rules page. Part VII of the rules states: "The standard distances shall be: Road Mile (1609.344m), 5km, 10km, 15km, 10 Miles, 20km, Half-Marathon, 25km, 30km, Marathon (42.195km), 50km, 100km and Road Relay." Two of those figures are not round numbers in metric terms: the Road Mile's 1,609.344m, which is the imperial mile converted exactly, and the marathon's 42.195km, which comes from one specific course.

The marathon's distance comes from one specific course, run once, then fixed in place years later. World Athletics' own account of the marathon: "The distance was later extended to the imperial measurement of 26 miles at the 1908 Olympic Games in London, and increased another 385 yards when the starting line was pulled back so it could be seen by the children in the Royal Nursery at Windsor and still finish in front of Queen Alexandra at the White City Stadium in west London." That 26-mile, 385-yard course, run once in 1908, became the fixed international standard 13 years later: "This distance was standardised at 26 miles 385 yards (42.195km) in 1921."

The half marathon is defined as exactly half that figure. World Athletics states it directly on its half marathon page: a half marathon is "exactly half the length of a marathon, at 13.1094 miles or 21.0975km."

The one non-road distance in the table, the 400-meter track lap, comes from a rule about track construction. World Athletics' 400 metres page states: "The 400m is a track event in which athletes complete one lap of a standard outdoor 400m athletics track while running in a designated lane." A standard lap runs slightly short of a quarter mile: 400 meters converts to 0.2485 miles, while an old-style quarter-mile track, 440 yards, measured 402.336 meters.

How long each distance takes at common finish times

Runked's own guides to these distances already publish reference finish times: median finishers from aggregated race results for the 5K through the marathon, and Running Level's Intermediate standard for the mile. The table below pulls the reference figure from each guide, so a runner sizing up a new distance can see roughly what a typical result looks like before running it.

The 5K through marathon rows describe a wide field of finishers; the mile row is Running Level's modeled Intermediate standard for ages 20s to 30s. A first attempt at any of these distances lands in the slower "first-timer" band each linked guide publishes separately from the median figures above. Compare a finish time to your own last one, not to the runner next to you; in Runked the rank starts everyone at Bronze and only moves on your own runs. See how the running rank works.

Turn the top table into a plan in three steps. First, convert whatever unit a plan, watch or race entry uses into the one that's familiar, using the top table above. Second, follow that distance's own link in the top table: 5K, 10K, half marathon and marathon each point straight to the matching training plan. Third, for a personal goal time on a new distance, project it from a recent run at a different distance using Runked's race-time predictor guide; the medians in the table above describe a wide field of finishers, useful for general context on a distance not yet run.

Common mistakes with distance conversions

• Rounding a 5K down to "3 miles." The extra 0.1 mile, about 160 meters, is easy to lose in casual conversation but shows up on a GPS watch as a short course if a route is measured to exactly 3.0 miles.
• Calling a half marathon "13 miles." The real figure is 13.1094 miles; the missing tenth of a mile lands right at the point in the race where pacing is already tight.
• Treating a 400-meter track lap as a literal quarter mile. It's close, 400m against a quarter mile's 402.336m, but converting track splits to road-mile pace using "4 laps = 1 mile" introduces a small, compounding error over longer track workouts.

What to do next

Once the numbers are settled, the usual next question is training. 5K training plan, 10K training plan, half marathon training plan and marathon training plan each break the matching distance above into a week-by-week build. Couch to 5K guide is the starting point if 3.1 miles is still further than a current long run.

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