Vertical Jump Calculator

The jump-and-reach method

You only need a wall, a tape measure and some chalk or a sticky note. The jump is the gap between how high you can reach standing and how high you can touch at the top of a jump.

Standing reach: stand side-on to the wall, feet flat, and reach straight up with the hand nearest the wall. Mark the highest point your fingertips touch.

Jump touch: from the same spot, dip and jump straight up, touching the wall as high as you can at the top. Chalk on the fingertips leaves a clear mark.

Getting a clean measurement

Swinging your arms changes the result, so decide whether you swing them and keep that choice for every test. Land softly with bent knees, and clear the area around the wall before you jump.

• Warm up first, then take three to five jumps with a full rest between them, and keep the best one.
• Jump from both feet without a step or a run-up, since a run-up adds height that the test is not meant to measure.
• Measure reach with your shoulder fully stretched up. A lazy reach makes the jump look bigger than it is.
• Use the same wall, shoes and rules every time you test, so later results are comparable.

From height to power

Jump height tells you how high, but not how much work your legs did. A heavier person who jumps the same height has produced more power. The calculator uses the equation from Sayers and colleagues, published in 1999: peak power in watts = 60.7 × jump height in cm + 45.3 × body mass in kg, minus 2,055.

Sayers built the equation from jump data in 108 college-age men and women and recommended it over two older equations, including one by Harman and colleagues from 1991. The example, a 20 inch jump at 180 lb, gives about 4,727 W, or about 58 W per kg.

How much to trust the watts

Any equation like this has a margin. For the Sayers equation the standard error is about 355 W, and it tends to come in low. That makes the number better for tracking your own change over time than for comparing yourself with someone tested on a lab force plate.

Body weight changes between tests also move the watts, even when the jump stays the same. Look at the inches and the watts per kg together before you decide that something has changed.

Using the result in training

Test every few weeks rather than every session, since one jump on a tired day says little. Set your watts per kg beside other measures, such as a squat max or your place on the strength standards, to see how strength and speed are moving together.

Related pages

Beep Test Calculator, Grip Strength by Age