Dunk Calculator

Choose centimetres or inches, enter your measured standing reach, then check the rim height. The default rim is 304.8 cm, or 10 ft. For an adjustable hoop, use its actual current height. Standing reach is the distance from the floor to your raised fingertip, not the distance to the top of your head.

Set the target hand height above the rim next. 0 places the fingertip target at rim height; 15 places it 15 cm above the rim. The default 15 cm is an example for exploring the calculation, not a universal dunk standard. Current vertical jump is optional; enter it to see current jumping reach and the remaining gap.

Valid inputs update the results automatically. If a required field is blank or invalid, correct it to see the new result. Reset restores the centimetre example and clears the optional current jump.

• Standing reach and rim height accept 1–500 cm; target clearance accepts 0–100 cm.
• Optional current vertical jump accepts 0–300 cm. These are input limits, not typical ability ranges.
• In inch mode, enter total inches: a 10 ft rim is 120 inches. Switching units converts existing entries.

Standing height runs from the floor to the top of your head; standing reach runs from the floor to your highest raised fingertip. Two people of the same height can have different reaches because of arm length, shoulder position, body proportions and how they extend the arm. Adding a fixed allowance to body height hides these differences.

Jumping reach is the highest point you can touch during a jump. Subtract standing reach to get your vertical jump. Do not enter the full touch height as your current jump, or standing reach will be counted twice.

Stand on a firm, level floor beside a suitable vertical measuring reference. Keep both feet flat without rising onto your toes, extend one arm overhead, and measure the vertical distance from the floor to the highest fingertip. Avoid a tilted tape, a scale that starts above the floor, or lifting your heels to make the mark.

To compare your current jump, record the highest touch point during a jump and subtract standing reach measured under the same conditions. For example, a 230 cm standing reach and 310 cm jumping reach give an 80 cm vertical jump. Enter 80 in the optional field, not 310.

Record whether you used an approach, a one-foot or two-foot takeoff, and the footwear and arm convention. Standing and approach jumps are different tests. Body displacement or jump height calculated from flight time by another device may also differ from a touch-height difference. Repeated measurements help check a reading; extra decimal places do not remove measurement error.

• Use consistent footwear, measuring surface and units for standing and jumping measurements.
• Check the test method before comparing with your earlier records.
• Do not climb or use unstable measuring equipment to mark a reading.

First add your chosen clearance to rim height to obtain the fingertip target height. Subtract standing reach to find the vertical displacement needed to reach it. The tool also calculates the jump to touch rim height, making the distinction between the rim and your chosen higher target explicit.

If the target is already within standing reach, the required jump is 0. That means no extra height is needed to reach that level; it does not establish that you can control the ball and complete a dunk.

Centimetre and inch entries are normalized before calculation, so the length relationships stay the same. 1 international inch is exactly 2.54 cm and 1 foot is 12 inches. Results are rounded for display; do not repeatedly convert already rounded screen values to assess tiny differences.

Take a standing reach of 230 cm, a rim height of 304.8 cm and a chosen hand clearance of 15 cm. Touching rim height requires 304.8 − 230 = 74.8 cm of vertical displacement. The hand target is at 319.8 cm, requiring a jump of 319.8 − 230 = 89.8 cm.

Now enter a current jump of 80 cm. Current jumping reach is 230 + 80 = 310 cm, which is 5.2 cm above the rim but 9.8 cm below the chosen hand target. Reaching rim height and reaching the selected clearance target can therefore produce different answers at the same time.

Keeping standing reach and the test method unchanged, a current jump of 90 cm gives a 320 cm jumping reach and a remaining gap of 0. This only says the entered reach exceeds the selected 319.8 cm height. It does not confirm a successful dunk or predict how long such a change would take.

The default 10 ft converts to exactly 304.8 cm under the international inch definition. FIBA equipment rules specify the upper edge of the ring at 3,050 mm, or 305 cm, with a tolerance of ±6 mm. The nominal difference between 304.8 and 305 cm is 0.2 cm, or 2 mm. They should not be described as identical; enter the measured height for your hoop.

Adjustable hoops and nonstandard courts may use other heights. The table fixes standing reach at 230 cm and chosen clearance at 15 cm while changing only rim height. These are arithmetic scenarios, not recommended hoop settings by age.

Touching a ring with your fingers and putting a ball through it are different actions. Ball size, hand size, grip, a one-handed or two-handed finish, takeoff position and finishing posture all affect the movement. No single fingertip clearance guarantees a dunk for everyone, so the target remains adjustable.

With a current jump entered, current jumping reach equals standing reach plus current jump. Extra jump to target is target height minus current jumping reach, with a lower limit of 0. If current jump is blank, these two results are omitted rather than treating unknown ability as 0.

A gap of 0 means the entered jumping reach meets or exceeds your chosen hand height. The tool does not show excess height as a negative gap and does not automatically certify dunk success. To compare targets, change clearance while keeping measurement method and other entries consistent.

The diagram places standing reach, rim, target and optional current jumping reach on one floor scale. It compares heights rather than body positions, ball movement or takeoff technique. If two levels look close, use the numbers to check the gap.

Try different rim heights or hand targets, or compare measurements from the same jump test. When comparing people, use each person’s measured reach: an equal vertical jump does not give everyone the same final touch height.

The tool does not estimate arm length from height, assess strength, speed, coordination or technique, or provide a training plan, injury assessment, rate of improvement or target date. Measurement error, changed testing methods and movement conditions affect readings. One web calculation cannot establish a lasting change in ability.

An extra 9.8 cm is the calculated gap under your chosen conditions. It does not say whether or how quickly you can gain it. For a visual comparison of people, use standing body height in the free 3D tool, not standing reach.

• Do not enter body height as standing reach or jumping reach as current vertical jump.
• Keep touching the rim, reaching a chosen hand target and completing a dunk distinct.
• Do not treat approach jumps, standing jumps and readings from different devices as identical tests.