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Vertical Jump Power (Lewis) Calculator

Turn your jump into watts.

How it is calculated

The tool applies the Lewis formula, which estimates peak power from body mass and the square root of jump height.

P = √4.9 × m × √h × 9.81

m is body weight in kilograms and h is the jump height in metres. The form takes the height in centimetres and divides it by 100 before using it. The constant √4.9 × 9.81 is about 21.715, so the formula reduces to roughly 21.715 × m × √h. The result is peak power in watts, to 2 decimals. Height and weight must both be above zero. It is an estimate from a regression-style formula and does not replace a force-plate measurement.

Worked example

An athlete weighing 80 kg jumps 45 cm. Convert the height: 45 ÷ 100 = 0.45 m, and √0.45 ≈ 0.6708. The constant is about 21.715. Multiply: 21.715 × 80 × 0.6708. The estimated peak power is 1,165.37 W, which is about 14.6 W per kg of body weight.

Try this example →

Common mistakes

  • Entering the jump height in metres (0.45) or inches. The field is in centimetres, and 0.45 would be read as less than half a centimetre.
  • Entering the reach height, such as standing reach plus jump, instead of the jump height alone. Use the difference between standing reach and jump reach.
  • Entering body weight in pounds instead of kilograms.
  • Expecting power to rise in direct proportion to height. Power depends on the square root of height, so a jump twice as high gives only about 1.41 times the power.
  • Comparing the result with force-plate figures. This is an estimate from height and mass only and usually differs from measured peak power.

About this calculator

The Lewis formula estimates peak anaerobic power output from a vertical jump using only body mass and jump height — the reasoning behind it goes back to the basic work-energy relationship that lifting a mass m through a height h against gravity requires work equal to mgh, and the Lewis nomogram converts that work into an estimated peak power figure in watts using body mass and the square root of jump height.

Strength and conditioning coaches use it as a low-cost field alternative to force-plate testing for the countermovement or Sargent jump test, since all it requires is a jump-and-reach measurement and a bathroom scale rather than laboratory equipment, making it common in team sports testing batteries even though force-plate or contact-mat systems are considered more accurate for tracking power changes over time.

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