10/29/2026
A 25-minute 5K doesn't automatically mean you can run a 50-minute 10K.
Wish it worked like that though.
You finish a 5K, look at your time and think, okay, double the distance, double the time. Easy enough.
Then you get to 7K and suddenly those last 3 kilometers feel VERY long.
Here's what the numbers suggest.
A 25:00 5K works out to roughly 52:07 for a 10K using a common race prediction formula.
That's over 2 minutes slower than simply doubling your 5K time.
Of course, some runners will beat that estimate. Others won't get close. Depends a lot on your endurance and how you train.
But it's a useful reminder that being fast over 5K and holding that speed for twice the distance aren't quite the same thing.