Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
Convert marathon → km
About this conversion
marathon and km are common length measurements.
Worked examples
Why this conversion matters
The marathon distance — 42.195 km (26.2 miles) — comes up constantly in training: converting weekly mileage targets, comparing your long-run distance to race distance as a percentage, and working out exactly how far is left at each kilometre marker on race day.
FAQ
Why is a marathon exactly 42.195 km?
The distance was fixed at the 1908 London Olympics (26 miles from Windsor Castle to the stadium, plus 385 yards so the race finished in front of the royal box) and later standardised internationally in metric terms.
How many kilometres should my longest training run be before a marathon?
Most training plans peak at 29-32 km (around 70-75% of race distance) for the longest single run, run 2-3 weeks before race day.
Is a marathon always run on a flat, accurately measured course?
Record-eligible marathons must be certified to the exact 42.195 km distance with a verified elevation drop limit, but not all marathons are record-eligible or perfectly flat.