Free negative split calculator
Save your fastest running for the second half.
Build a simple first-half and second-half pacing plan for 5K, 10K, half marathon or marathon.
Your plan
First half 2:01:00
Second half 1:59:00
When a negative split helps
A small negative split can prevent an over-fast opening from turning into a large slowdown. Keep the difference modest, rehearse it in training, and adjust for hills and weather.