About this calculator
Choose even splits, or a negative split where the second half is a little faster, a strategy many runners use for their best times.
How to use it
- Choose the distance.
- Enter your goal time.
- Choose 0% for even splits or a small percentage for a negative split.
The formula
Even pace = goal time ÷ distance; negative split: second-half pace = first-half pace × (1 − %)
- goal time
- your target finish time
- %
- how much faster the second half is
Worked example
10 km in 50:00
- Even pace: 5:00 per km, halfway at 25:00.
- With a 2% negative split: about 5:03 per km for the first half and 4:57 for the second, still finishing in 50:00.
What the result means
Going out too fast is the most common racing mistake; a slight negative split protects against it.
Assumptions
- Flat course.
Limitations
- Adjust for hills and water stations.
Frequently asked questions
What is a negative split?
Running the second half of a race faster than the first.
How much faster should the second half be?
1% to 3% is typical.
Why use splits?
To check during the race whether you are on track for your goal.
Not medical advice. This calculator is a general screening tool and cannot diagnose any condition. Results are estimates. Please talk to a doctor or a qualified health professional about your health and before making changes to diet, exercise or treatment.
Last reviewed on 1 October 2026. Found a mistake? Tell us.