Choose a value to solve for using the legacy Lewis equation: its power estimate, body mass, or jump height. Units and calculation details are included.
Vertical Jump Power Formula
This calculator retains the historical Lewis equation for a power estimate from body mass and jump-and-reach height. It does not directly measure peak or takeoff power. Sayers et al. (1999) found their squat-jump regression more accurate for peak power than Lewis. Reverse modes give algebraic model values, not independent physical measurements.
In this equation, body mass has a direct effect on the result, while jump height affects the result through a square-root relationship. That means larger jumps increase estimated power, but not in a perfectly linear way.
| Symbol | Meaning | Typical Unit |
|---|---|---|
| Pj | Legacy Lewis power estimate | W |
| BW | Body mass used in the calculation | kg |
| JRS | Vertical jump height | m |
If jump height is determined from reach testing, calculate it first as:
The same formula can also be written in a shorter form:
How to Calculate Vertical Jump Power
- Measure body mass in kilograms.
- Measure vertical jump height in meters.
- Take the square root of the jump height.
- Multiply by body mass and the constants in the formula.
- Express the final result in watts.
This makes the calculator especially helpful when you want more context than jump height alone. Two athletes may jump the same height, but the heavier athlete can still produce a higher estimated power output.
Example Calculations
Example 1: An athlete with a body mass of 75 kg records a vertical jump height of 0.60 m.
Example 2: An athlete with a body mass of 82 kg records a vertical jump height of 0.55 m.
How to Interpret Vertical Jump Power
- Higher model values reflect the entered mass and jump height; they do not establish measured explosive power.
- Mass influences the result, so power should not be interpreted the same way as jump height alone.
- Testing method matters; squat jumps, countermovement jumps, and jumps with arm swing should be compared separately.
- Consistency matters; use the same warm-up, surface, footwear, and measurement method when tracking progress.
- This is an estimate, which makes it practical for field testing, but it is not the same as direct force-plate measurement.
Common Input and Measurement Tips
- Enter vertical jump height, not total reach from the floor.
- Keep units consistent; centimeters should be converted to meters before using the formula.
- If you measure with standing reach and jump reach, use the same technique each time for cleaner comparisons.
- Use unloaded jump-and-reach testing; this calculator does not validate the Lewis equation for loaded jumps.
- If multiple trials are performed, use either the best jump or the average jump based on your testing standard.
Unit Conversions
Vertical jump power is usually reported in watts, but it can also be expressed in horsepower.
Common jump-height conversions are:
