Free Basketball Performance Tool

Can IDunk?

Enter your height and vertical jump to find out instantly — and if not, exactly how close you are and what it will take.

Your Measurements

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Standing Reach
Vertical Needed
Gap to Dunk
How Close Are You?
Can't touch rim Can touch rim Can dunk
Your Path to Dunking
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How High Do You Need to Jump to Dunk?

Dunking requires getting your hand high enough above the 10-foot rim to push the ball through. Most players need their dunking hand at least 6 inches above the rim — meaning your fingertips need to reach approximately 10 feet 6 inches.

Your standing reach — the height of your fingertips with your arm fully extended — is the starting point. The difference between 10'6" and your standing reach is how high you need to jump.

Height Est. Standing Reach Vertical Needed to Dunk Difficulty
5'7"7'3"~39–43"Extremely rare
5'9"7'6"~36–40"Very hard
5'11"7'8"~32–36"Hard
6'0"7'10"~28–32"Challenging but achievable
6'2"8'0"~24–28"Realistic with training
6'4"8'3"~20–24"Achievable for most athletes
6'6"+8'6"+~16–20"Accessible

The Role of Arm Length

Arm length is the hidden variable most people ignore. Two players who are both exactly 6 feet tall can have wildly different standing reaches depending on their wingspan. A player with unusually long arms may have a standing reach of 8'2" while a player with short arms of the same height may only reach 7'9".

Every extra inch of standing reach is one fewer inch you need on your vertical jump. Athletes with long wingspans have a massive natural advantage when it comes to dunking.

Famous Short Dunkers

Spud Webb (5'7") won the 1986 NBA Slam Dunk Contest with a reported 46-inch vertical. Nate Robinson (5'9") won three NBA Dunk Contests. Isaiah Thomas (5'9") has dunked in NBA games. All three had exceptionally long wingspans relative to their height and trained explosiveness obsessively.

One-Foot vs. Two-Foot Takeoff

Your takeoff style affects how you should train and how achievable dunking is for your body type.

Two-foot takeoff (power dunk): You jump from both feet simultaneously, usually from a slow approach or standing start. This requires more raw vertical jump height but is more consistent. Most strength training directly improves two-foot jumping.

One-foot takeoff (approach dunk): You jump off one foot after a running approach, using the elastic energy of your stride. This allows many athletes to jump 2–5 inches higher than their standing vertical because momentum converts into upward force. Most people who dunk for the first time do it off one foot.

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Pro tip: If you're close to dunking, practice one-foot approach jumping before anything else. Many athletes discover they can dunk off an approach when their standing vertical says they shouldn't be able to. The running start adds significant height for most people.

How to Add Inches to Your Vertical Fast

Phase 1 — Quick Wins (Weeks 1–4)

Before training a single extra day, two things can immediately improve your effective jump height: approach mechanics and arm swing. A well-timed two-step approach with an explosive arm swing can add 3–5 inches of effective height over a flat-footed jump. Practice your approach at the rim every day.

Phase 2 — Build Explosive Strength (Weeks 1–12)

Heavy squats are the foundation. Get your squat to 1.5× bodyweight and you'll see your vertical jump follow. Add depth jumps — step off a 12-inch box, land, and immediately explode upward — twice per week to train the reactive strength that converts into dunking power.

Phase 3 — Sprint Training (Weeks 4–12)

Sprinting and jumping use overlapping muscle recruitment. Athletes who sprint regularly jump higher. Add two sprint sessions per week — 6 × 30-yard dashes at full effort — and your vertical will respond.

Frequently Asked Questions

Can a 5'9" person dunk?
Yes, but it requires an exceptional vertical of approximately 35–40 inches. At 5'9" with average arm length, your standing reach is around 7'6", meaning you need to clear 10'6" — a gap of 3 feet. This requires years of dedicated training and the right genetics. Nate Robinson (5'9") won three NBA Dunk Contests, so it's absolutely possible — just very hard.
Can a 6 foot person dunk?
Yes — a 6-foot person with average arm length needs roughly a 28–32 inch vertical to dunk. That's above average but achievable for a dedicated athlete. At 6 feet, dunking is a realistic 6–12 month training goal for most people who start with at least a 20-inch vertical.
How long does it take to learn to dunk?
It depends how close you are. If you're within 4 inches, expect 2–3 months of focused training. If you're 6–10 inches away, expect 4–8 months. If you're more than 12 inches away, expect 9–18 months of consistent squat and plyometric training. The closer you are, the faster you'll get there.
Does losing weight help you dunk?
Significantly. Losing fat while maintaining strength improves your power-to-weight ratio, which directly increases your vertical jump. Losing 10 pounds of fat while keeping the same squat strength can add 2–4 inches to your vertical. For many athletes close to dunking, leaning out is the fastest path to their first dunk.
What is the shortest person to ever dunk?
The most famous short dunker is Spud Webb at 5'7", who won the 1986 NBA Slam Dunk Contest. Webb reportedly had a 46-inch vertical. More recently, players as short as 5'5" have claimed to dunk, though these aren't formally verified. Webb's win remains one of the most iconic moments in basketball history.