Split calculator
Plan your race split by split. Choose even pace, or run the second half slightly faster with a negative split.
| km | Split | Pace | Elapsed |
|---|
Turn this result into a full Race Pace Plan. Tell us your race and goal time. You get one PDF with:
- Goal pace and splits for your race
- Training paces for all five zones
- A printable pace band
Why a small negative split works
Starting slightly slower than goal pace saves glycogen and keeps lactate low early in the race. Most marathon records have been set with even or slightly negative splits. A gap of 1–2 % between halves is a good target for most runners.
The calculator keeps your goal time fixed. The first half runs at average pace plus half the gap, the second half at average pace minus half the gap. Read more in how to pace a marathon.
Common questions
What is a negative split?
Running the second half of a race faster than the first. A 1 % negative split in a 3:30 marathon means about 1:45:53 for the first half and 1:44:07 for the second.
Should I bank time early?
No. Time banked in the first half is usually lost with interest in the last 10 km.
Can I print a pace band?
Yes. The free Race Pace Plan includes a printable pace band for your goal time.