How high do I need to jump to dunk?

Take the rim height (305 cm on a standard hoop), add the clearance you need above the rim to control the ball (usually about 15 cm), and subtract your standing reach. Someone with a 238 cm standing reach needs 305 + 15 - 238 = 82 cm of vertical jump to dunk, but only 67 cm to touch the rim.

What is standing reach and how do I measure it?

Standing reach is the height your fingertips reach when you stand flat-footed and stretch one arm straight overhead. Stand side-on to a wall, keep both heels on the floor, reach up with the arm closest to the wall and mark the highest point you can touch. If you cannot measure it, standing reach is typically about 1.33 times your height, so a 180 cm person reaches roughly 240 cm.

What vertical jump is realistic?

Most untrained adults jump around 40 to 50 cm from a standing start. Trained athletes commonly reach 60 to 90 cm, and elite jumpers exceed 100 cm. A running two-foot or one-foot jump usually adds 10 to 20 cm over a standing jump, which is why most people attempt dunks off a run-up.

Dunk Calculator

This dunk calculator tells you how high you need to jump to dunk a basketball, based on your standing reach, the rim height and how much clearance you want above the rim. Standing reach is the key number: it is the height your fingertips reach when you stand flat on the floor and stretch one arm straight up, and it matters far more than your height alone, because two people the same height can differ in reach by 10 cm or more through arm length and shoulder width. The calculator subtracts your reach from the rim height to give the vertical needed just to touch the rim, then adds your chosen clearance, usually about 15 cm so your hand and the ball can get over the front of the ring, to give the vertical needed for a genuine dunk. The default rim height is 305 cm, the standard 10 foot hoop used everywhere from school courts to the NBA. If you have never measured your standing reach, stand side-on to a wall, keep both heels down and mark the highest point you can touch, or estimate it as roughly 1.33 times your height. Then compare the answer with typical trained verticals of 60 to 90 cm to see how far off the dunk you really are.

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Standing reach

Rim height

Clearance above the rim

82 cm

vertical jump needed to dunk

To touch the rim67 cm

Rim height305 cm

Clearance allowed15 cm

Verticals are measured from a standing start. A running jump typically adds 10 to 20 cm, and you also need hand size or ball control to palm or cradle the ball on the way up. Estimate only.

How it works

The vertical needed to touch the rim is the rim height minus your standing reach, and the vertical needed to dunk is the rim height plus your clearance minus your standing reach. Clearance is the extra height your hand and the ball need above the front of the ring to throw the ball down rather than graze the iron; around 15 cm suits most people, while bigger hands and better ball control can get away with less. If your reach already exceeds the rim plus clearance, the calculator shows zero, because you could dunk flat-footed. Measure standing reach honestly: flat feet, one arm fully extended, no shrugging onto your toes. If you cannot measure it, multiply your height by about 1.33; the true figure varies with arm length, so a measured reach always beats an estimate.

Worked example

Say you are about 180 cm tall with a measured standing reach of 238 cm, and you are aiming at a standard 305 cm rim with 15 cm of clearance. To touch the rim you need 305 - 238 = 67 cm of vertical, which is within range for a trained jumper. To dunk you need 305 + 15 - 238 = 82 cm, a serious vertical that most people only reach with dedicated jump training and a running approach. If a season of training lifts your standing vertical to 65 cm and a run-up adds another 18 cm, you arrive at 83 cm of effective jump, and the dunk is on. Lower the rim to 275 cm at a training hoop and the requirement drops to 52 cm, a realistic place to practise the movement.

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