A half marathon is 21.1 km (more precisely 21.0975 km).

Quick Scoop

  • Standard half marathon distance: 21.1 km.
  • In miles, that’s about 13.1 miles.
  • It’s exactly half of a full marathon (42.2 km / 26.2 miles).

If you’re training, most plans and races will round it to 21 km , but official race measurements use 21.0975 km for accuracy.

“Think of the half marathon as the natural next step after a 10K – long enough to feel epic, short enough to be realistic for busy people.”

Mini FAQ

  • Q: Is a half marathon 20 km or 21 km?
    A: Officially just over 21 km (21.0975 km); most runners casually say 21.1 km.
  • Q: Why that weird number?
    A: Because it’s defined as exactly half of the official marathon distance (42.195 km), so you get 21.0975 km.

TL;DR: A half marathon is 21.1 km, or 21.0975 km if you want the exact official distance.

Information gathered from public forums or data available on the internet and portrayed here.