Ask whether a 5’9″ player can dunk and you will get two confident answers: no, too short, and yes, with enough bounce. Both miss the point, because height is not the variable that decides a dunk. Standing reach is. The rim sits 10 feet high, the hand must clear it with the ball, and the gap between the reach and the rim is what the legs must supply. A 5’9″ player with a long reach and a big vertical dunks. A 6’2″ player with a short reach and a small vertical does not. This guide works the formula for every height in the question, explains how to measure the two numbers that matter, and sets out honestly what training can and cannot change.

The formula: rim, reach, and the 6 inches

A regulation rim is 10 feet above the floor, which is 120 inches or 3.05 metres, in every major code of the game. To dunk, the hand holding the ball must get above the rim, and not by a whisker: the ball itself must clear the rim, and the hand must control it over the rim, which in practice needs the hand about 6 inches above the rim for a one-handed dunk, the figure the Dunk Calculator uses. The vertical jump required is therefore the rim height, plus 6 inches, minus the standing reach — the height the fingertips touch with feet flat and one arm stretched up. In symbols: vertical needed equals 126 minus standing reach, in inches. Every other consideration in this guide is commentary on those three numbers.

Worked example, the one the calculator opens with: a player with an 8-foot standing reach, 96 inches, needs 126 minus 96, which is 30 inches of vertical jump. A player with a 92-inch reach needs 34 inches. A player with a 100-inch reach needs 26 inches. The formula is linear and unforgiving: every inch of reach is worth an inch of vertical, and there is no way to trade anything else against it except the 6 inches of clearance, which can be trimmed by dunking two-handed with a smaller ball clearance or by palming the ball, but not by much, and never to zero — the ball still has to get over the rim. Anyone selling a dunk program that ignores reach is selling the wrong variable.

The formula also runs backwards, which is the more useful direction for most players. If your vertical jump is 30 inches, the reach you need is 126 minus 30, which is 96 inches, or 8 feet. If your vertical is 36 inches, you need a reach of 90 inches, 7 feet 6 inches. Measure the vertical you actually have, subtract it from 126, and you know the reach that would let you dunk; measure the reach you actually have, subtract it from 126, and you know the vertical you need. The Dunk Calculator does both directions, and the honesty of the whole exercise is in measuring both numbers properly, which is the subject of the measuring section below.

The reach table: what each reach demands

Vertical needed equals 126 inches minus standing reach. The 6 inches of hand above the rim is included.

Read the table as a ladder. The top rows are steep country: a 42-inch vertical is elite even among professional athletes, and a player who needs it is, in practical terms, not going to dunk without a very unusual combination of gifts and training. The middle rows are the realistic battleground for most committed players: 30 to 34 inches is well above the average untrained vertical, but it is a range that dedicated strength and jump training can reach for some athletes, and it is where the question “can I dunk?” is genuinely open. The bottom rows are comfortable: a 22-inch vertical is within reach of many active players, which is why taller players with long arms dunk with what looks like little effort — the formula was kind to them before they ever trained.

Height, reach, and why they are not the same

Height and standing reach are related, but the relationship is loose enough to decide dunking outcomes. Reach depends on height plus arm length plus shoulder width and mobility, and arm length varies considerably between people of the same height: wingspan, the fingertip-to-fingertip span, is often close to height, but it can exceed height by several inches or fall short of it, and two players of the same height can differ by 4 or 5 inches of reach. Four inches of reach is four inches of vertical in the formula — the difference between needing 30 inches and needing 34, which is the difference between a hard goal and a very hard one. That is why this guide refuses to publish a table of “vertical needed at each height”: any such table must assume a reach for each height, and the assumption would be wrong for a large share of readers.

The practical consequence is simple: measure your reach, do not estimate it from your height. Stand flat-footed beside a wall, reach one arm straight up, and mark the highest fingertip touch. That is the standing reach the formula uses, with the same arm you would dunk with, and it should be measured in shoes you play in, because an inch of sole is an inch of reach. Players sometimes report reach measured on tiptoe, or with a jump, or with both arms — all of which inflate the number and understate the vertical needed, producing a pleasant answer and a failed dunk. The wall, flat feet, one arm, playing shoes: that is the measurement, and it takes thirty seconds.

5’2″, 5’9″, 5’10”, 5’11”: the question, answered properly

The search questions come in heights, so here are the heights, answered the honest way: as the vertical each height needs for a range of reaches, so that any reader can find their own row. A player at 5’9″ with a 92-inch reach needs 34 inches. With a 96-inch reach the same player needs 30 inches. With an 88-inch reach, 38 inches. The height alone settles nothing; the reach settles the requirement, and the vertical settles whether it is met. What can be said about 5’9″ in general is that it is short for dunking but not prohibitively so: the requirement typically lands in the low-to-mid 30s, which demands serious bounce, and the players at this height who dunk are the ones who have it, usually built over years of jumping sports and strength training, not over a summer.

At 5’10” and 5’11”, the picture improves by the inches of reach those heights usually, not always, bring. A 5’11” player with a 96-inch reach needs 30 inches; with a 100-inch reach, 26 inches. That is why dunking becomes common, though never universal, around 6 feet: the requirement falls into the high 20s, where a good athlete with training often lands. At 5’2″, the honest answer is the hardest: the requirement typically lands in the 40s, because a 5’2″ player’s reach is usually in the low 80s, and a vertical in the 40s is rare at any height. It is not impossible — short players with extraordinary bounce exist, and the formula shows exactly what combination would be needed — but it should not be presented as a normal goal, and any program promising it to a typical 5’2″ player should be treated with scepticism. The formula does not care about fairness. It cares about inches.

One more height question deserves a direct answer: does dunking get easier with age or growth? For teenagers, yes, mechanically: growth adds height and usually reach, and the requirement falls as reach grows, sometimes by several inches in a year. For adults, height is fixed, and the only variables that move are reach, through shoulder mobility and posture, by an inch at most, and vertical jump, through training. The productive question for an adult is therefore not “will I grow into it?” but “what is my reach, what is my vertical, and how much can training move the vertical?” The training section takes that question seriously.

Measuring your reach and your vertical honestly

Standing reach: flat feet, one arm up, fingertip mark on a wall, in playing shoes, as described above. Take the best of three tries, with the shoulder stretched but the heels down. Vertical jump: the honest methods are a jump-and-reach test against a wall or a Vertec device, or a jump mat or force plate where available. Stand beside the wall, mark the standing reach, then jump from a standstill and mark the highest touch; the difference is the standing vertical. For a running vertical, take two or three approach steps, as in a game, and mark the highest touch; the difference from standing reach is the running vertical, which is usually several inches higher, and which is the relevant number for a dunk off an approach. Record which one you measured. Quoting a running vertical as a standing vertical, or a Vertec reading taken with a generous reach mark, inflates the number and corrupts the formula.

Two measurement traps are worth naming. The first is the reach mark taken on tiptoe or with a shrug that lifts the shoulder: it adds inches that the jump cannot use, because the jump starts from flat feet. The second is the vertical measured with a countermovement so deep it resembles a squat, or with a step, neither of which matches the jump used at the rim. Measure the jump you will actually use: a quick dip and explode, off one foot or two as you prefer, with the ball in hand if you want the full picture, because holding a ball costs a little height. A measurement that survives those controls is a number you can plan from. A measurement that does not is a story.

Training the gap: strength, bounce, and technique

The vertical jump is trainable, and the gap between a player’s current vertical and the requirement is the training target. The two pillars are strength and speed of force production. Strength work — squats, deadlifts, split squats, calf raises, done with progressive overload and good technique — raises the force the legs can produce. Plyometric work — jumps, bounds, box jumps, depth jumps, done fresh and with full recovery — teaches the legs to produce that force quickly, which is what a jump is: force in a fraction of a second. Either pillar alone under-delivers: strength without speed is a slow push, and plyometrics without a strength base is bouncing on a weak spring. Most programs combine both, two or three sessions a week, with jumping kept fresh rather than done to exhaustion, because tired jumps teach slow jumps.

Technique is the third pillar, and it is free. The approach matters: a controlled two- or three-step approach, a penultimate step that lowers the hips, a plant that converts horizontal speed into vertical lift, and an arm swing that adds height rather than fighting it. One-foot and two-foot jumping suit different bodies: longer, lighter players often jump higher off one foot with speed, while stronger, heavier players often do better off two feet with a deep dip, and the only way to know is to measure both. Ball control matters too: palming the ball, or controlling it with two hands to the rim, costs less height than fumbling it, and practising the gather and the finish at sub-maximal heights builds the timing that a first dunk needs. None of this is quick. Meaningful vertical gains are measured in months and years, not weeks, and they come with injury risk if volume and landing mechanics are ignored: warm up, land softly, progress gradually, and stop when joints complain.

Realistic expectations protect both knees and motivation. An untrained adult vertical in the high teens or low 20s is common. Dedicated training can add several inches, and for some athletes a great deal more, but the distribution is wide and genetics — tendon stiffness, muscle fibre mix, limb proportions — sets a ceiling that effort alone does not move. A player who needs 30 inches and currently jumps 24 has a real goal. A player who needs 42 and jumps 20 has a goal that training alone is very unlikely to close, and the honest advice is to enjoy the game for everything else it offers, which is a great deal. The formula gives the requirement; training gives the trajectory; only measurement over time tells you which side of the line you are on.

Dunking in a game is not dunking alone

Everything so far assumes an empty gym, a clear run, and a ball delivered perfectly. A game adds defenders, fatigue, traffic, and a rim that must be attacked at speed and often off balance. The first in-game dunk usually comes later than the first practice dunk, and it comes on a breakaway or an open cut, not in traffic. The gap between practice and game is mostly timing and courage: reading the opening, committing to the jump with a defender near, and finishing through contact. Practising dunks in pickup games, at low rims first and then at full height, bridges the gap better than any amount of solo jumping, because it trains the decision as well as the leap.

There is also a safety dimension that practice dunking hides. Dunking loads the knees, ankles, and Achilles heavily on landing, and hanging on the rim — tempting, and celebrated — is penalised in most organised play and risks injury to the hands and shoulders. Land on two feet where possible, give way on the knees, and avoid dunking through fatigue, when landing mechanics deteriorate first. The rim is 10 feet high in every gym; the floor is hard in every gym; and the difference between a highlight and a sprain is usually the landing, not the leap.

What the formula does not see

The formula sees three numbers and nothing else. It does not see hand size: a player who cannot palm the ball must control it with two hands or cup it against the wrist, which costs a little height and changes the finish. It does not see arm length relative to height beyond what the reach measurement already captures — which is why reach, not height, is the input. It does not see approach speed, jump technique, fatigue, or the defender. It does not see the difference between a standing vertical and a running vertical, and the calculator asks which you measured for that reason. And it does not see the ball: a smaller or softer ball is easier to control, which is why youth and practice balls flatter the requirement, and why a first dunk with a game ball, at game pressure, is a stricter test than the formula alone suggests.

None of that makes the formula useless. It makes it a starting point: the requirement, stated exactly, from which training and practice proceed. Measure the reach honestly, measure the vertical honestly, subtract, and you know where you stand. The rest — the training, the timing, the first dunk itself — is the work, and it is work worth doing even if the rim stays just out of reach, because the strength, bounce, and coordination it builds change every other part of the game too.

Frequently asked questions

Can you dunk at 5'9"?

It depends on your standing reach and your vertical jump, not on height alone. With a 92-inch reach you need a 34-inch vertical; with a 96-inch reach you need 30 inches. Both are well above average and need serious jump training, but a 5’9″ player with that combination of reach and bounce can dunk. Measure both numbers honestly and the formula gives your own answer.

Can you dunk at 5'2"?

Very rarely. A 5’2″ player typically has a reach in the low 80s, which puts the vertical requirement in the 40s, a range few athletes at any height reach. It is not impossible, and the formula shows exactly what combination of reach and vertical would be needed, but it should not be treated as a normal goal, and programs promising it to a typical 5’2″ player should be viewed sceptically.

How high does my vertical need to be to dunk?

Subtract your standing reach from 126 inches: rim height of 120 inches plus 6 inches of hand above the rim. A 96-inch reach needs 30 inches, a 92-inch reach needs 34 inches, and a 100-inch reach needs 26 inches. Measure your reach flat-footed, one arm up, in playing shoes, and measure the vertical you will actually use, standing or running.

Is it easier to dunk off one foot or two feet?

It depends on the player. Longer, lighter players often jump higher off one foot with a running approach, while stronger players often do better off two feet with a deeper dip. Measure both. The calculator uses the vertical you enter, so enter the one that matches the jump you will use at the rim, and be consistent when tracking progress.

Do I need to palm the ball to dunk?

No, but it helps for a one-handed dunk. Players who cannot palm the ball dunk two-handed, cupping the ball, or control it against the wrist and forearm. Hand size affects the finish and the control, not the height requirement in the formula, though fumbling the ball at the rim can cost the inches the formula says you have.

How long does it take to gain enough vertical to dunk?

Meaningful gains take months of consistent strength and plyometric training, and for many players years. An untrained vertical in the high teens or low 20s is common, and dedicated training can add several inches, with wide individual variation. Track the standing and running vertical monthly, under the same measurement conditions, and judge progress by the measurements, not by feel.