Can I Dunk Calculator: Vertical Jump Needed to Dunk a Basketball
Find out if you can dunk: compare your standing reach plus vertical jump with a 10 ft rim (or 9, 8, 7 ft), see the vertical you need, how short you are, and the take-off speed it takes.
How it works
Max touch = standing reach + vertical jump · Vertical needed to dunk = rim height + clearance − standing reach · Margin = max touch − (rim + clearance) · Take-off speed = √(2 g h) · Hang time = 2√(2h ÷ g)
Whether you can dunk depends on how high your hand gets, not on your height alone. Your standing reach (floor to fingertip with one arm straight up) plus your vertical jump gives your max touch height. To dunk, your hand has to get the ball over the rim and push it down, so you need to reach roughly 6 inches (15 cm) above a regulation 10-foot (3.05 m) rim. That makes the vertical you need: 10 ft + 6 in − standing reach, or 126 in − reach. Enter your measured standing reach for the most reliable answer. If you have not measured it, the calculator can estimate it as height × 1.33, but arm length and shoulder width vary, so the estimate can be off by several inches. You also get the vertical needed to just touch the rim, a table for 7, 8, 9 and 10 ft rims and the take-off speed and hang time your jump needs, from basic projectile physics. The vertical jump calculator on this site turns jump height into power and hang time; this page answers the yes-or-no dunk question and the gap to close.
Worked example
You are 5 ft 10 in tall with a measured standing reach of 92 in (7 ft 8 in) and a 26 in vertical. Your max touch is 92 + 26 = 118 in (9 ft 10 in). Dunking on a 10 ft rim needs 120 + 6 = 126 in, so the vertical needed is 126 − 92 = 34 in and you are 8.0 in short (to touch the rim you need 28 in). A 34 in jump needs a take-off speed of √(2 × 32.17 × 2.833) = 13.5 ft/s and keeps you in the air for 0.84 s. On a 9 ft rim you would need 22 in, which you already have.
Sources: Calculate.co.nz: Dunk calculator (rim + clearance − reach, 15 cm clearance, reach ≈ height × 1.33) · Fitness Volt: Vertical jump calculator (dunk reach, 6 in allowance, 8 ft reach example) · Omni Calculator: Dunk calculator (rim heights by grade, hang time and take-off speed) · The Hoops Geek: Dunk calculator (6 in default extra reach)
Frequently asked questions
How high do you need to jump to dunk?
Subtract your standing reach from 126 inches (a 10 ft rim plus about 6 in to get the ball over). With an 8 ft (96 in) standing reach you need about a 30 in vertical; with 7 ft 6 in (90 in) you need about 36 in.
How tall do you have to be to dunk?
There is no fixed height. Standing reach is usually about 1.33 times height, so a 6 ft (72 in) player reaches about 96 in and needs roughly a 30 in vertical, while a 5 ft 9 in player needs about 34 in. Many players under 6 ft dunk with a strong approach jump.
How do I measure standing reach?
Stand flat-footed side-on to a wall, reach straight up with the arm nearest the wall and mark the highest point your middle finger touches. Measure from the floor to the mark. Shoes add about an inch.
Is a running vertical higher than a standing vertical?
Usually, yes. Most athletes jump a few inches higher off a run-up and a one- or two-foot gather, which is how most dunks happen. Enter the jump you will actually use.
What is the difference between touching the rim and dunking?
Touching the rim only needs your fingertips to reach 10 ft. Dunking needs the ball, which is about 9.4 in across, held above the rim and pushed down, so you need roughly 6 in more reach unless you can palm the ball.
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This calculator is for educational purposes. Double-check important results before acting on them.