Running Interval Calculator
Plan an interval session and the total volume it produces.
About Running Interval Calculator
The work to rest ratio determines what the session trains: ratios near one to one develop aerobic capacity while much longer recoveries allow faster, more anaerobic repetitions. Distance at intensity rather than total distance is what drives the training adaptation, which is why a ten kilometre session can be easier than a six kilometre one.
Formula
Running Interval
Session time = repetitions × rep time + recoveries + warm-up and cool-down
- work to rest ratio
- Rep duration divided by recovery duration
- distance at intensity
- Total distance covered at the target pace
Worked example
With the default values below, Running Interval Calculator returns Total Session Time of 45.70. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Repetitionsminimum 1
- 8
- Distance per repetitionminimum 1 m
- 400 m
- Target time per repetitionminimum 1 s
- 84 s
- Recovery between repetitionsminimum 0 s
- 90 s
- Warm-up and cool-down distanceminimum 0 km
- 4 km
Results
- Total Session Time
- 45.70 min
- Distance at Intensity
- 3.200 km
- Total Session Distance
- 7.200 km
- Repetition Pace
- 3.5000 min/km
- Work to Rest Ratio
- 0.933
Step by step
- 1Values used
- 2Running Interval
- 3Total Session Time= 45.70 min
- 4Distance at Intensity= 3.200 km
- 5Total Session Distance= 7.200 km
- 6Repetition Pace= 3.5000 min/km
- 7Work to Rest Ratio= 0.933
Assumptions and limits
- The result is derived only from the 5 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 4 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 Running Interval calculated?
Session time = repetitions × rep time + recoveries + warm-up and cool-down The work to rest ratio determines what the session trains: ratios near one to one develop aerobic capacity while much longer recoveries allow faster, more anaerobic repetitions.
Why does Running Interval matter?
Distance at intensity rather than total distance is what drives the training adaptation, which is why a ten kilometre session can be easier than a six kilometre one.
What values do I need to enter?
This calculator takes 5 inputs: Repetitions, Distance per repetition, Target time per repetition, Recovery between repetitions, Warm-up and cool-down distance. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.