Swimming Split Calculator
Break a swim time into even splits by lap and see the pace needed for each length.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Estimate target splits from distance, total time, pool length and a pacing scenario. First and final split adjustments are illustrative percentages, not a personalized training prescription. For a partial final length, its target time is scaled to the remaining distance.
Worked example
calculated with the default values below
Race distance 400 m · Target time — minutes 6 min · Target time — seconds 0 s · Pool length 25 m · Pacing Even splits Average per full pool length 0:23 · Target pace per 100 m 1:30 · Number of lengths 16 · First length split 0:23 · Final length split 0:23
General background references
Disclaimer
These calculators give general mathematical results. They suit study, planning and estimation — verify anything that feeds a graded submission, a published figure or a financial commitment.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
L = ⌈d ÷ p⌉; t = (60m + s) ÷ L
- d
- Total distance (m)
- p
- Pool length (m)
- m
- Minutes
- s
- Seconds
- L
- Number of lengths
- t
- Time per length (s)
Average full-length split = total time × pool length ÷ distance; per 100 m = total time × 100 ÷ distance. The last partial length is prorated to its remaining distance. Scenario factors adjust only the displayed first/last splits (fast start: 0.96/1.04; negative: 1.02/0.98); they are illustrative and do not form a complete schedule.
Frequently asked questions
How are the first and final swim splits estimated?
The even baseline is total time divided by distance and scaled to the pool length; a partial final length is prorated to its remaining distance. Fast-start and negative-split options apply illustrative multipliers only to the displayed first and final sections. They are not a full split schedule or a prediction.