Training Impulse (TRIMP) Calculator

Work out training impulse (trimp) instantly with clear inputs, formula shown and shareable results.

About Training Impulse (TRIMP) Calculator

Banister's TRIMP weights duration by intensity using an exponential factor that reflects the lactate response: load = minutes x HR ratio x 0.64 e^(1.92 x HR ratio). At 145 bpm with 55 resting and 185 maximum the ratio is 0.69, giving a weighting of 2.4 and about 100 TRIMP for an hour. The exponential means hard sessions count far more than their duration alone suggests.

Formulas

Heart rate ratio

ratio = (avg HR - resting HR) / (max HR - resting HR)

TRIMP

TRIMP = minutes x ratio x 0.64 x e^(1.92 x ratio)

Worked example

With the default values below, Training Impulse (TRIMP) Calculator returns Training Impulse of 100.4. Change any input above and every figure here is recalculated in your browser.

Inputs used

Session durationminimum 0 min: 60 min
Average heart rateaccepts 40–230 bpm: 145 bpm
Resting heart rateaccepts 25–140 bpm: 55 bpm
Maximum heart rateaccepts 60–230 bpm: 185 bpm

Results

Training Impulse: 100.4 TRIMP
Fraction Of Heart Rate Reserve: 0.6923
Intensity Weighting Applied: 2.418
Session Assessment: Hard session

Step by step

1Values used
2Heart rate ratio
3TRIMP
4Training Impulse= 100.4 TRIMP
5Fraction Of Heart Rate Reserve= 0.6923
6Intensity Weighting Applied= 2.418
7Session Assessment= Hard session

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 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.
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.

This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.

Frequently Asked Questions

Why an exponential weighting?

Because blood lactate rises exponentially with intensity, so a linear weighting would badly understate the physiological cost of hard efforts.

Is the male coefficient different from the female one?

Banister's original used 1.92 for men and 1.67 for women. This calculator uses the widely quoted 1.92 form.