Vertical jump
power calculator

Peak leg power in watts from your vertical jump and body mass, using the Sayers (1999) equation. With watts per kilogram, the error band, and the comparison equation most tools leave out.

How the math works

Vertical jump power estimates the peak mechanical power your legs produce in a jump, from two inputs: the jump height (the jump-and-reach differential — jump reach minus standing reach) and your body mass. The headline number uses the Sayers peak-power equation (Sayers et al., 1999), which was cross-validated against force-plate measurement and recommended over the older equations it compared against.

A single Sayers equation is used for men and women — the paper found using one equation for both sexes changed the estimate by only about 5%. The 45.3 × body mass term is why a heavier athlete scores more watts at the same jump height, and why the honest cross-bodyweight comparison is watts per kilogram.

Worked example

An athlete weighing 185 lb (83.9 kg) records a 24-inch (61 cm) vertical jump.

• Peak power: 60.7 × 60.96 + 45.3 × 83.9146 − 2055 = 5,447 W
• Relative power: 5,447 ÷ 83.9146 = 64.9 W/kg
• Estimate band (±355 W): roughly 5,092–5,802 W
• Harman 1991 comparison: 8,616 W — about 3,170 W higher for the same jump

The gap between Sayers and Harman is the point of the comparison: the same jump gives two very different watt figures depending on which published equation you use. A calculator that prints one number to the watt is quoting a regression whose error bar the equation's own authors put at hundreds of watts.

When this calculator is wrong

The watt number rewards bodyweight, so it ranks the heavier athlete first at the same jump height — which makes raw watts the wrong axis for comparing explosiveness across sizes. Sayers et al. (1999) fitted peak power at 60.7 × jump height (cm) + 45.3 × body mass (kg) − 2055, so the estimate rises about 453 W for every extra 10 kg at an unchanged jump. Two athletes both jumping 50 cm: a 70 kg athlete scores 4,151 W (59.3 W/kg), a 90 kg athlete 5,057 W (56.2 W/kg) — the heavier one leads by 906 W on watts but trails on watts per kilogram. The exception is a task where moving your own body is the whole point — a rebound, a block, a dunk attempt — where the absolute watts delivered to accelerate that mass is exactly the relevant number; W/kg is for comparing between athletes, not for the jump itself.

• It's an estimate, not a measurement. The peak-power equation's standard error of estimate was 355 W on the squat-jump protocol that fit it best (Sayers 1999), and larger on a countermovement jump-and-reach, which is what most field tests actually use. Read the watts with a band of a few hundred, not to the single digit.
• The equation choice moves the number more than the athlete does. The older Harman (1991) equation returns roughly 3,000 W more than Sayers for the same jump. Sayers cross-validated Harman and found it overestimates peak power — but the spread is a reminder that "watts" is a modelled quantity, not a physical reading.
• Population validity. Both equations were fitted on physically active, college-age adults. Applied to children, older adults, or elite jumpers whose jumps sit outside that range, the estimate drifts, and at very small jumps and body masses the −2055 intercept can drive it to meaningless low or negative values.

What to do with the result

Use watts per kilogram, not raw watts, whenever you compare athletes of different sizes or track one athlete through a bodyweight change — it's the number that isolates power from mass. For a single athlete, the most useful move is to retest at a fixed protocol (same jump type, same measurement method) and watch the trend: the equation and its error are held constant, so a rising W/kg is a real change even though the absolute watt figure carries a wide band. If you want the tightest input the equation supports, measure a squat jump rather than a countermovement jump-and-reach, since that is the protocol Sayers fitted most closely. And pair the jump with a maximal-strength number — the two describe different qualities.

Common questions

How do you calculate power from a vertical jump?

The common method is a regression from jump height and body mass. The cross-validated one is Sayers et al. (1999): peak power (W) = 60.7 × jump height (cm) + 45.3 × body mass (kg) − 2055. Jump height is the jump-and-reach differential (jump reach minus standing reach). The result is an estimate of peak anaerobic power, in watts.

Does body weight affect vertical jump power?

Yes — heavily. The equation has a +45.3 × body mass (kg) term, so at the same jump height a heavier athlete is estimated to produce more watts (about 453 W more per extra 10 kg). That's real physics — more mass accelerated is more power — but it means raw watts favour size. To compare explosiveness across bodyweights, divide by mass and use watts per kilogram.

Which vertical jump power formula is most accurate?

Sayers et al. (1999) cross-validated three equations (Lewis, Harman 1991, and their own) against force-plate power and recommended the Sayers peak-power equation, which underestimated measured power by less than 1% with a standard error of estimate of 355 W. The Lewis and Harman equations were less accurate; Harman overestimated. That's why this page leads with Sayers and shows Harman only as a comparison.

What is a good vertical jump power in watts?

There isn't a clean primary normative table to quote, and because the watt figure scales with body mass, a single "good" number would mislead — a heavier athlete posts higher watts at the same jump. Compare on watts per kilogram instead, and against your own retests over time, rather than against a fixed threshold. Where you want an absolute benchmark, jump height itself is the cleaner comparison.

Can I use a countermovement jump or does it have to be a squat jump?

You can use either, but know the trade-off. Sayers (1999) found the squat jump gave the tighter fit (the 355 W error band), because countermovement-jump technique varies more between attempts. Most field tests use a countermovement jump-and-reach, which is fine — just read the result with a slightly wider band than the squat-jump number implies.

Is vertical jump power the same as leg strength?

No. Power is work per unit time — how fast you can express force — while maximal strength is the most force you can produce regardless of speed. They're related but distinct: a strong lifter isn't automatically a powerful jumper. Pair this with a one-rep-max estimate to see both qualities.