CALCULATOR 25

Race Splits Calculator

The time to hit at every kilometre or mile for your goal finish time.

Average pace

Enter a goal time between 1:00 and 100:00:00.

For general information only; not medical advice. Consult a qualified professional before making health decisions.

How this is calculated

Even pace

Split = goal time ÷ distance

Negative split by x%

First half = goal time ÷ (2 − x/100)
Second half = first half × (1 − x/100)

A split that crosses halfway gets the right share of each half's pace. The last split is shorter when the distance isn't a whole number of km or miles.

Sources

Daniels J (2014), Daniels' Running Formula, 3rd ed. Human Kinetics; Daniels J, Gilbert J (1979), Oxygen Power: Performance Tables for Distance Runners.

Even or negative splits

Most distance records are run at close to an even pace, or slightly faster in the second half. Starting too fast costs more time later than it saves early. A negative split of 1–3% means holding back for the first half and finishing strong, which suits most runners from 10K up.

Read more about the Race Splits calculator

Using your splits

Check your watch at each marker and aim to stay within a few seconds of the plan. Hills, wind and crowded starts will move individual splits; it's the cumulative time that matters.

Frequently asked questions

What is a negative split?

Running the second half of a race faster than the first. A 2% negative split on a 50-minute 10K means about 25:15 then 24:45.

What pace for a sub-2-hour half marathon?

5:41 per km, or 9:09 per mile, run evenly.

Should I run even splits in a marathon?

Even or slightly negative is safest. Going out fast is the most common reason for slowing badly in the last 10 km.