Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
Convert half marathon → km
About this conversion
half marathon and km are common length measurements.
Worked examples
Why this conversion matters
A half marathon is 21.0975 km (13.1 miles) — runners training for the distance need this figure constantly: for pacing splits, for converting a training-plan's weekly mileage target, and for comparing race times across courses measured in different units.
FAQ
How many kilometres is a half marathon exactly?
21.0975 km — the distance is standardised worldwide by World Athletics, identical whether the race is run in the UK, US or anywhere else.
Why isn't a half marathon a round number like 21 km?
It's defined as exactly half of a full marathon (42.195 km), and the marathon distance itself comes from a specific 1908 Olympic course length that was later standardised.
What's a good half marathon pace for a beginner?
Most first-time half marathon runners aim for 6:30-7:30 per km (around 2 hours 15 minutes to 2 hours 40 minutes finish time), though this varies widely by fitness level.