๐ Dunk Calculator: How High Do You Need to Jump to Dunk?
By Shihab Mia ยท Updated 2026-07-11
Standing reach is how high you touch with one arm straight up, flat-footed. Do not know it? Estimate it below.
How far your hand clears the rim so the ball drops in. 6 in is a safe default.
Standing reach is roughly 1.33 x your height. This is an average, real reach varies with arm length.
| Height | Est. standing reach | Vertical to dunk |
|---|
This dunk calculator tells you the exact vertical jump you need to dunk a basketball. Enter your standing reach, the rim height, and how much clearance you want above the rim, and it does the arithmetic in inches and centimetres. For a player with a 7 ft 6 in (90 in) standing reach aiming at a standard 10 ft rim with 6 inches of clearance, the required vertical jump is 36 inches (about 91 cm). Most players who can already dunk sit in the 28 to 34 inch range on a regulation rim. Change any input and the answer updates instantly.
What is the Dunk Calculator?
Dunking is a reach problem before it is an athleticism problem. To throw the ball down through the hoop, the highest point of your hand has to get roughly 6 inches above the rim so the ball clears cleanly. The rim on a regulation hoop sits at 10 feet, which is 120 inches. So the height your hand must reach at the top of your jump is the rim height plus your clearance: 120 + 6 = 126 inches. Everything the dunk calculator does flows from that single target number.
Your standing reach is the other half of the equation. It is how high you can touch with one arm stretched straight overhead while standing flat on the floor, and it already includes your arm span above your head. That matters because two people who are the same height can have very different standing reaches depending on their arm length, so measuring your actual reach gives a far better answer than guessing from height alone. Once you know your standing reach, the vertical jump you need is simply the target minus that reach: required vertical jump = rim height + clearance - standing reach.
Work the default example through and you can see why the vertical jump to dunk is so demanding for shorter players and so easy for tall ones. A standing reach of 90 inches leaves 126 - 90 = 36 inches to make up with your legs. Add just a few inches of reach, say to 96 inches, and the required jump drops to 30 inches. Take the reach up to 108 inches (common for players around 6 ft 10 in) and the number falls to 18 inches, which many athletes can hit without any special training. This is exactly why the dunk calculator asks for reach rather than height: reach is what the physics actually cares about.
How much clearance you need depends on how you finish. A one-handed dunk, where you palm the ball and drop it in, needs your hand only a few inches above the rim, so 4 to 6 inches of clearance is realistic. A two-handed dunk requires both wrists over the rim and usually wants a couple more inches, closer to 6 to 8. Grip matters too: if you cannot palm the ball, you have to cup it against your forearm and get even higher, effectively adding an inch or two to the target. The calculator lets you set the clearance so you can model the exact finish you are training for.
If you have never measured your standing reach, this calculator can estimate it for you from your height. A widely used rule of thumb is that standing reach is about 1.33 times your height, because arm length scales roughly with overall body size. For a 6 ft 0 in (72 in) player that gives an estimated reach of about 96 inches, and therefore a required vertical of about 30 inches to dunk on a 10 ft rim. Treat that as a starting point, not gospel: long-armed players will need less jump than the estimate says, and short-armed players will need more. Whenever you can, measure your real reach and type it in.
The vertical jump to dunk is a target you can train toward, and the physics of the jump is worth understanding. Your hang time (the total time you are airborne) is fixed by how high you rise: a 24 inch vertical keeps you up about 0.70 seconds, a 36 inch vertical about 0.86 seconds. The relationship is t = 2 x sqrt(2h / g), where h is jump height and g is gravity (9.8 m/s squared), and it is why adding even 2 inches of vertical noticeably increases the window you have at the rim. Numbers in the 20 to 30 inch range are realistic for committed athletes who train strength, plyometrics, and technique over months. Beyond about 35 to 40 inches you are into the vertical leaps of high level college and professional jumpers. The dunk calculator does not tell you how long it will take to add inches to your jump, but it does give you the exact gap to close, which is the first thing any training plan needs. You can also lower the rim to 9 feet (108 inches) for a youth hoop and watch the required jump drop sharply, because the tool is just doing rim height plus clearance minus standing reach, honest arithmetic you can trust.
When to use it
- Find out whether you can already dunk, or exactly how many inches of vertical jump you still need.
- Set a concrete vertical jump goal before starting a jump training or plyometrics program.
- Estimate your standing reach from your height when you have no way to measure it directly.
- Compare the jump needed on a full 10 ft rim versus a lowered 9 ft youth rim.
- Check the difference a one-handed versus two-handed dunk makes by adjusting the clearance above the rim.
- See how your target vertical translates into hang time and how much air you actually have at the rim.
How to use the Dunk Calculator
- Enter your standing reach: the height you can touch with one arm straight up while standing flat-footed.
- Set the rim height, which defaults to the regulation 10 ft (120 in), or lower it for a youth hoop.
- Set the clearance you want above the rim; 6 inches is a sensible default so the ball drops in cleanly.
- Read the required vertical jump shown in both inches and centimetres, along with a plain-language verdict.
- If you do not know your standing reach, type your height into the estimate box and click Use estimate to fill it in.
- Switch between feet/inches and centimetres with the unit toggle, and use Copy summary to save your numbers.
Formula & method
Worked examples
A player with a 7 ft 6 in standing reach wants to dunk on a regulation 10 ft rim with 6 inches of clearance.
- Convert standing reach to inches: 7 ft 6 in = 7 x 12 + 6 = 90 in.
- Rim height in inches: 10 ft = 120 in.
- Target height for the hand = rim + clearance = 120 + 6 = 126 in.
- Required vertical jump = target - standing reach = 126 - 90 = 36 in.
- Convert to metric: 36 x 2.54 = 91.4 cm.
Result: A 36 inch (91.4 cm) vertical jump is needed to dunk.
A 6 ft 0 in player does not know their standing reach and wants an estimate, then the required jump.
- Convert height to inches: 6 ft 0 in = 72 in.
- Estimate standing reach = height x 1.33 = 72 x 1.33 = 95.76 in (about 96 in).
- Target height = 120 + 6 = 126 in.
- Required vertical jump = 126 - 95.76 = 30.24 in (about 30 in).
- In centimetres: 30.24 x 2.54 = 76.8 cm.
Result: The estimated vertical jump to dunk is about 30 inches (77 cm).
A player with a 36 inch vertical wants to know their hang time, how long they hover near the rim.
- Convert jump height to metres: 36 in x 0.0254 = 0.914 m.
- Apply the hang time formula: t = 2 x sqrt(2h / g) = 2 x sqrt(2 x 0.914 / 9.8).
- Inside the root: 2 x 0.914 / 9.8 = 0.1866; its square root is 0.432.
- Total air time: t = 2 x 0.432 = 0.86 seconds.
Result: A 36 inch vertical gives roughly 0.86 seconds of hang time from takeoff to landing.
Vertical jump needed to dunk by standing reach (regulation 10 ft rim, 6 in clearance, target 126 in)
| Standing reach | Reach in inches | Vertical jump to dunk |
|---|---|---|
| 7 ft 0 in | 84 in | 42 in (106.7 cm) |
| 7 ft 3 in | 87 in | 39 in (99.1 cm) |
| 7 ft 6 in | 90 in | 36 in (91.4 cm) |
| 7 ft 9 in | 93 in | 33 in (83.8 cm) |
| 8 ft 0 in | 96 in | 30 in (76.2 cm) |
| 8 ft 6 in | 102 in | 24 in (61.0 cm) |
| 9 ft 0 in | 108 in | 18 in (45.7 cm) |
| 9 ft 6 in | 114 in | 12 in (30.5 cm) |
Estimated standing reach and vertical needed by height (reach = height x 1.33, 10 ft rim, 6 in clearance)
| Height | Estimated standing reach | Vertical jump to dunk |
|---|---|---|
| 5 ft 8 in | 90.4 in | 35.6 in (90.3 cm) |
| 5 ft 10 in | 93.1 in | 32.9 in (83.6 cm) |
| 6 ft 0 in | 95.8 in | 30.2 in (76.8 cm) |
| 6 ft 2 in | 98.4 in | 27.6 in (70.1 cm) |
| 6 ft 4 in | 101.1 in | 24.9 in (63.3 cm) |
| 6 ft 6 in | 103.7 in | 22.3 in (56.5 cm) |
| 6 ft 8 in | 106.4 in | 19.6 in (49.8 cm) |
Vertical jump converted to hang time (air time from takeoff to landing, t = 2 x sqrt(2h / g))
| Vertical jump | Jump height (m) | Hang time (seconds) |
|---|---|---|
| 12 in | 0.305 m | 0.50 s |
| 18 in | 0.457 m | 0.61 s |
| 24 in | 0.610 m | 0.71 s |
| 30 in | 0.762 m | 0.79 s |
| 36 in | 0.914 m | 0.86 s |
| 42 in | 1.067 m | 0.93 s |
| 48 in | 1.219 m | 1.00 s |
Common mistakes to avoid
- Using height instead of standing reach. Height ignores arm length. Two 6 foot players can have reaches that differ by several inches, which changes the required jump by the same amount. Always use standing reach when you can, and only fall back to the height estimate when you must.
- Forgetting the clearance above the rim. Just touching the rim is not a dunk. Your hand needs to clear the rim, usually by about 6 inches, so the ball can go down through the hoop. Leaving clearance out makes the jump look easier than it really is.
- Measuring standing reach on your toes. Standing reach must be measured flat-footed. If you rise onto your toes while measuring, you fold part of your jump into the reach and the calculator will understate the vertical you need.
- Ignoring grip and hand size. If you cannot palm the ball, you have to cup it against your wrist or forearm and get higher than someone who can grip it one-handed. Add an inch or two of clearance to reflect a weaker grip, or train ball control alongside your vertical.
- Assuming a youth 9 ft rim needs the same jump. A 9 ft rim is 108 inches, so the target drops to 108 + 6 = 114 in. That is a full foot lower than a regulation hoop and cuts 12 inches off the required vertical. Set the rim height to match the hoop you actually play on.
- Confusing vertical jump with a running jump. Most players jump higher off a running approach than from a standstill. The dunk calculator gives the vertical you need at the rim; whether you hit it off one foot or two, standing or running, is up to your technique.
Glossary
- Dunk
- A shot where the player jumps and pushes the ball down through the hoop from above the rim.
- Standing reach
- The height you can touch with one arm stretched straight overhead while standing flat-footed. It already includes your arm length above your head.
- Vertical jump
- How many inches your reach increases from a jump, measured from your standing reach to the highest point you touch in the air.
- Rim height
- The height of the basketball hoop off the floor, 10 feet (120 inches) on a regulation court, often 9 feet for youth play.
- Clearance
- The extra height above the rim your hand needs so the ball drops cleanly through, commonly about 6 inches.
- Target height
- Rim height plus clearance; the height your hand must reach at the top of the jump. On a regulation rim it is 126 inches.
- Hang time
- The total time you spend in the air from takeoff to landing. It depends only on jump height, not on body weight or approach.
- Approach jump
- A jump taken with a running start, which usually produces a higher vertical than a standstill jump.
Frequently asked questions
How high do you need to jump to dunk?
It depends on your standing reach. The vertical jump to dunk equals rim height plus clearance minus your standing reach. For a typical 90 inch reach on a 10 ft rim with 6 inches of clearance, you need a 36 inch (91 cm) vertical jump. Most players who can dunk on a regulation rim sit in the 28 to 34 inch range. Enter your own reach above for an exact number.
What standing reach do I need to dunk without jumping much?
To dunk you must reach 126 inches (rim 120 plus 6 inches clearance). If your standing reach is already 126 inches or more you can dunk flat-footed. A reach of about 114 inches leaves only a 12 inch vertical, which most athletic players can manage.
Can a 6 foot person dunk?
Yes, but it takes work. A 6 ft 0 in player has an estimated standing reach near 96 inches, so the required vertical jump is about 30 inches. That is a solid but achievable target with dedicated jump training, and long-armed 6 footers need even less.
How do I measure my standing reach?
Stand flat-footed next to a wall, stretch one arm straight up, and mark the highest point your fingertips touch. Measure from the floor to that mark. Keep your heels down; measuring on your toes will make the dunk calculator understate the jump you need.
Does the dunk calculator work if I do not know my standing reach?
Yes. Use the estimate box to enter your height and it fills in a standing reach of about 1.33 times your height. This is an average, so measure your real reach when you can for a more accurate vertical jump to dunk.
How high is a standard basketball rim?
A regulation basketball rim is 10 feet, which is 120 inches or about 305 cm, off the floor. Youth games often use a lowered 9 ft rim. Set the rim height in the dunk calculator to match the hoop you play on.
What is hang time and how does it relate to my vertical?
Hang time is how long you stay airborne, from takeoff to landing. It depends only on jump height: a 24 inch vertical gives about 0.71 seconds, a 36 inch vertical about 0.86 seconds, and a 48 inch vertical about 1.0 second. The formula is t = 2 x sqrt(2h / g). Even 2 extra inches of vertical meaningfully widens your window at the rim.
Do I need to palm the ball to dunk?
Not necessarily, but it helps. If you can palm the ball one-handed you need only a few inches of clearance. If you cannot grip it, you cup the ball against your wrist or forearm and have to get an inch or two higher, so add that to your clearance in the calculator.
How much easier is dunking on a 9 foot rim?
A 9 ft rim is 108 inches, so the target becomes 114 inches instead of 126. That cuts the required vertical jump by 12 inches compared with a regulation hoop, which is why youth players dunk far more easily on a lowered rim.
Does a running start change the jump I need?
No, the height you must reach is fixed by the rim and clearance. But most people jump higher with a running approach than from a standstill, so a running dunk can make a required vertical easier to hit than a standing one.