What one jump height already decides
How long you stay airborne and how fast your feet leave the floor are both fixed once the jump height is known. With air resistance ignored, the rise and the fall cover the same distance under the same acceleration, so hang time scales with the square root of the height. This page takes the jump height and returns the hang time, the rise time that is half of it, and the takeoff velocity in both feet per second and miles per hour. Add a standing reach and it also gives the highest point your hand reaches.
The equations applied are t = 2ā(2h/g) for hang time and v = ā(2gh) for takeoff velocity, with g taken as 9.80665 m/sĀ² (as of October 2026). Both come straight out of the free-fall assumption, so the output is only as accurate as the measured height. Hang time runs from the instant the feet leave the ground to the instant they land, and tucking the knees in the air does not change it.
No grade or level is assigned, because the vertical jump has no official grading table. This page also does not take bodyweight, so it produces no power figure in watts and no dunk verdict; for power, use a jump power calculator that takes bodyweight as well. Testing a maximal jump lands hard, so do it over a mat, and postpone max attempts if your knees or ankles hurt.
Frequently asked questions
Working the free-fall equation backwards gives about 48 inches. A full second of hang time means half a second up and half a second down, and that is how far gravity drops you in half a second. The long hang you see in games mostly comes from horizontal travel and body position.
No. The vertical jump has no official grading table. Standards differ so much between sports and measurement methods that comparison is unreliable. This page reports only what the physics gives and assigns no level.
It does. A standing jump and a jump with an approach differ, and so do a reach-and-touch measurement and a belt-mounted device. Compare only figures captured the same way.