Reach advantage calculator
Put both fighters' numbers in and see the reach and height differentials, plus each fighter's ape index. It tells you what shape the matchup is — not who wins it.
The tale of the tape
Reach is measured fingertip to fingertip with both arms straight out at shoulder height — it is a wingspan, not an arm length.
The comparison
Your opponent is longer by 2.0 in.
Reach describes a matchup; it does not decide one. What you do with it shows up in the punch stats →
How the math works
Subtraction, and one ratio. The reach differential is your reach − their reach. Ape index is reach − height for each fighter, which tells you whether someone is long for their frame independent of how tall they are. The ratio underneath expresses the same thing as a multiple, which is easier to compare across weight classes.
Every number here is exact given correct measurements. All of the uncertainty on this page lives in the tape and in the interpretation, not in the arithmetic.
What a reach advantage actually buys you
Distance, and only if you use it. A longer fighter can land the jab from where the opponent cannot reply, and can score on entry as the shorter fighter closes. That is a real edge and it is also entirely conditional — it evaporates the moment the range collapses, which is exactly what a good shorter fighter spends the round trying to make happen.
The shorter fighter's advantage is leverage on the inside and a lower centre of gravity to work from. Neither body type is better. The tale of the tape tells you which fight each person needs to have.
Honest caveats
Published reaches are not always reliable. They get measured casually, copied between databases and occasionally rounded in a flattering direction, so two sources will sometimes disagree by an inch or more on the same fighter. If the number matters to you, measure it yourself.
More importantly: reach is descriptive, not destiny. No differential on this page predicts an outcome, and treating it as though it does is the most common way people misread a matchup. What you do with the range shows up in the punch stats, and where you fight it shows up in your weight class.
Common questions
How do I measure reach correctly?+−
Stand against a wall, arms straight out to the sides at shoulder height, and measure fingertip to fingertip. That is a wingspan, not an arm length — boxing has always listed it that way. Have someone else hold the tape; measuring your own span pulls one shoulder forward and shortens the number.
Does a reach advantage decide fights?+−
No. It changes what the fight looks like, not who wins it. A longer fighter can keep range and score on the way in; a shorter one gets inside where the longer fighter has no leverage. Both are workable, and neither is a prediction — plenty of great fighters have won consistently while giving up reach. Treat it as one line on a tale of the tape, not a forecast.
What is a good ape index?+−
There is no target. Ape index is reach minus height, so zero means your span matches your standing height, and most people sit within a couple of inches either side. A positive index is an advantage for keeping range and a disadvantage for infighting leverage. It describes a body, not a quality.
Why does boxing list wingspan rather than arm length?+−
Because wingspan is repeatable. Arm length depends where you decide the arm begins — acromion, shoulder joint, armpit — and different people measure it differently. Fingertip to fingertip against a wall gives the same number no matter who holds the tape, which matters when it is going on an official tale of the tape.
You cannot train your reach. You can train everything behind it.
Twelve weeks on the muscles a fighter runs on — the power chain from the floor through the hips into the shot.