Stand flat-footed and reach as high as you can against a wall.
function calculateDunkCapability() {
var reachFt = parseFloat(document.getElementById('reachFeet').value) || 0;
var reachIn = parseFloat(document.getElementById('reachInches').value) || 0;
var jump = parseFloat(document.getElementById('verticalJump').value) || 0;
var rim = parseFloat(document.getElementById('rimHeight').value) || 120;
var standingReachTotal = (reachFt * 12) + reachIn;
var maxTouch = standingReachTotal + jump;
var resultDiv = document.getElementById('dunk-result');
var messageSpan = document.getElementById('dunk-message');
var touchSpan = document.getElementById('total-touch');
var analysisDiv = document.getElementById('dunk-analysis');
if (standingReachTotal <= 0 || jump = rim
// Dunking (small hand/barely) = rim + 5 inches
// Solid Dunking = rim + 10 inches
if (maxTouch >= (rim + 10)) {
resultDiv.className = "status-success";
messageSpan.innerHTML = "Result: Elite Dunker!";
analysisDiv.innerHTML = "You are " + (maxTouch – rim) + " inches above the rim. You can likely perform windmill or 360 dunks.";
} else if (maxTouch >= (rim + 6)) {
resultDiv.className = "status-success";
messageSpan.innerHTML = "Result: You Can Dunk!";
analysisDiv.innerHTML = "You have about " + (maxTouch – rim) + " inches over the rim. This is enough to clear the ball over the iron comfortably.";
} else if (maxTouch >= rim) {
resultDiv.className = "status-warning";
messageSpan.innerHTML = "Result: Rim Grazer";
var diff = rim + 6 – maxTouch;
analysisDiv.innerHTML = "You can touch the rim, but you need about " + diff + " more inches of vertical to dunk a full-sized basketball.";
} else {
resultDiv.className = "status-danger";
messageSpan.innerHTML = "Result: Not Quite Yet";
var deficit = rim – maxTouch;
analysisDiv.innerHTML = "You are " + deficit + " inches away from even touching the rim. Focus on plyometrics and leg strength!";
}
}
How to Use the Dunking Calculator
Dunking a basketball is the ultimate feat of athleticism. To determine if you can dunk, it isn't just about your height; it's about the combination of your standing reach and your vertical explosiveness.
The Math Behind the Dunk
A standard NBA and FIBA basketball rim is exactly 10 feet (120 inches) high. To dunk a standard size-7 basketball, your hand doesn't just need to reach the rim—it needs to clear it by roughly 6 inches to ensure the ball doesn't hit the "back iron" and bounce out.
The formula for a successful dunk is typically:
Standing Reach + Vertical Jump ≥ 126 Inches
Key Measurements Explained
Standing Reach: This is measured by standing flat-footed and reaching as high as possible with one hand. For most people, this is roughly 1.3 to 1.4 times their height in inches, but long arms (wingspan) can provide a massive advantage.
Vertical Jump: This is the height you can lift your body off the ground from a standing start or a running start. For this calculator, use your max "leap" height.
The Clearance Factor: Touching the rim (120″) is a great milestone, but because a basketball is roughly 9.5 inches in diameter, your wrist generally needs to be at rim-level to finish a dunk cleanly.
Example Scenarios
Scenario A: A 6'0″ player with an 8'0″ (96″) standing reach. To dunk, they need a 30-inch vertical jump to touch the rim, but realistically a 36-inch vertical to dunk effectively.
Scenario B: A 6'6″ player with an 8'10" (106″) standing reach. They only need a 14-inch jump to touch the rim and a 20-inch jump to dunk, which is why taller players "make it look easy."
Tips to Increase Your Vertical Jump
Strength Training: Focus on squats, deadlifts, and Bulgarian split squats to build the raw power in your glutes and quads.
Plyometrics: Incorporate box jumps, depth jumps, and pogo hops to improve your "Rate of Force Development" (how fast you can explode).
Technique: Work on your "penultimate step"—the second to last step in a running jump that converts horizontal speed into vertical lift.