Vertical Jump Calculator

At the peak of a vertical jump your upward velocity is zero, and the climb takes the same time as the fall. Hang time t is symmetric, so t = 2 * v0 / g and h = v0^2 / (2g), which combine into h = g * t^2 / 8 with g = 9.81 m/s^2. A 0.5 second hang time works out to about 12 inches of vertical, a 0.65 second hang time to about 20 inches, and a 0.85 second hang time (NBA-level explosive jumper) to about 35 inches. The calculator runs that math in both inches and centimeters, and inverts it (t = 2 * sqrt(2h/g)) when you enter a jump reach instead.

The calculator uses fixed descriptive bands. Below 16 inches is below average, 16 to under 20 is average, 20 to under 24 is good, 24 to under 28 is athletic, 28 to under 34 is excellent, and 34 inches or more is elite. These labels are broad context only. The calculator does not adjust them for a population or produce a percentile.

The NBA Draft Combine reports standing vertical and maximum vertical as separate tests. Maximum vertical includes an approach, while standing vertical does not. The calculator does not apply an NBA average or convert one protocol into the other. Compare your result only with a result measured using the same method.

Hang-time mode assumes ideal projectile motion and splits the measured airtime evenly between ascent and descent. Reach mode subtracts standing reach from jump reach. Arm position, takeoff timing, landing posture, frame rate, and whether you use an approach can make the two results differ. Use the same protocol each time when tracking progress.

The calculator uses the Sayers equation P = 60.7 x jump height in cm + 45.3 x body mass in kg - 2055. It returns an estimated peak power in watts only when you enter a positive body weight and the equation produces a positive result. This is a regression estimate, not a direct force-plate measurement.