Swim Interval Calculator
Plan a swim interval set and the total volume and rest it involves.
About Swim Interval Calculator
Swimming sets are prescribed by send-off interval rather than rest, so faster swimmers earn more rest. The rest ratio is what determines whether the set develops endurance or speed. A set on a tight send-off becomes progressively harder as fatigue slows repetitions and rest shrinks, which is the intended stimulus.
Formula
Swim Interval
Rest = send-off interval − repetition time; total time = repetitions × send-off
- send-off interval
- The clock interval at which each repetition starts
- rest ratio
- Rest divided by work, which sets the training stimulus
Worked example
With the default values below, Swim Interval Calculator returns Total Set Time of 18.333. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Repetitionsminimum 1
- 10
- Distance per repetitionminimum 25 m
- 100 m
- Target time per repetitionminimum 1 s
- 95 s
- Send-off intervalminimum 1 s
- 110 s
Results
- Total Set Time
- 18.333 min
- Total Distance
- 1,000 m
- Rest per Repetition
- 15.0 s
- Pace per 100 m
- 95.00 s
- Intensity Note
- Moderate rest — aerobic capacity work
Step by step
- 1Values used
- 2Swim Interval
- 3Total Set Time= 18.333 min
- 4Total Distance= 1,000 m
- 5Rest per Repetition= 15.0 s
- 6Pace per 100 m= 95.00 s
- 7Intensity Note= Moderate rest — aerobic capacity work
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
- This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
Frequently Asked Questions
How is Swim Interval calculated?
Rest = send-off interval − repetition time; total time = repetitions × send-off Swimming sets are prescribed by send-off interval rather than rest, so faster swimmers earn more rest. The rest ratio is what determines whether the set develops endurance or speed.
Why does Swim Interval matter?
A set on a tight send-off becomes progressively harder as fatigue slows repetitions and rest shrinks, which is the intended stimulus.
What values do I need to enter?
This calculator takes 4 inputs: Repetitions, Distance per repetition, Target time per repetition, Send-off interval. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.