Racing smarter

What pace is a 45-minute 10K?

What pace is a 45-minute 10K?

45:00 over 10 km (6.21 mi) is 4:30/km (7:15/mi), held from the first step to the last. There is no rounding slack in that number: run the first kilometre at 4:40/km and you have already spent ten seconds you will not get back cheaply.

45 minutes is 4:30/km (7:14/mi) and it is one of the most useful benchmarks in running, because it maps cleanly onto other distances: roughly a 21:40 5K and a 1:40 half. Training is commonly four days a week at 35 to 50 km with one session of intervals or tempo. The failure mode at this target is pacing by feel on a hilly course. At 4:30/km the effort is high enough that a 30-metre climb changes your pace by 20 seconds a kilometre, and chasing the number up the hill costs more than the seconds it saves. Run the climbs on effort, take the pace back on the descent, and judge by total time.

What the splits look like

And in miles, for a course measured that way:

Where should I be at halfway?

Even pace puts you through halfway at 22:30. Most people who finish this time went through slightly slower than that, not faster — a 2% negative split means halfway at 22:57 and a second half of 22:03.

The decision rule for race day: if you reach halfway more than 0:27 ahead of 22:30, you are not ahead of schedule, you are borrowing. Ease back to 4:30/km (7:15/mi) and hold it.

What if my watch measures the course long?

Almost every watch does. A 10K that reads 1.5% long on your wrist means you have to run 4:26/km by the watch to finish in 45:00 by the clock. That is the pace to put on the screen, and it is why pacing off a watch's average-pace field alone tends to leave people a minute or two short.

See this on your own runs →