If you’ve ever heard runners, cyclists, or race organisers mention a “50K” distance, you might be wondering: how many miles is that exactly? 

Whether you’re preparing for your first ultramarathon, tracking fitness goals, or just curious, this guide will give you a clear, quick conversion! It will break down everything you need to know about the 50K distance.

Quick Answer: 50K in Miles

Here is a quick conversion of kilometers to miles:

1 kilometre (km) = 0.621 miles

Therefore,

50 kilometres = 50 * 0.621 = 31.07 miles

So when someone says, “I’m running a 50K in miles,” it means they’re covering just over 31 miles. To view it in a different light, a traditional marathon (26.2 miles) is 5 miles shorter than a 50K. This is the reason why it is referred to as the entry-level ultramarathon distance.

Why the 50K Distance Is Popular

The First Step into Ultramarathons

The 50K is the first experience of ultramarathon running for most runners. It is an easy step up to marathon training, but the challenge of travelling further than 26.2 miles is still there.