Measure your height
Take off your shoes. Stand tall against a wall, look straight ahead and keep your heels on the floor. Use a flat book to mark the top of your head, then measure from the floor.
APE13 / KNOW YOUR REACH
Ape index calculator
How does your reach measure up? Compare your arm span with your height and calculate your ape index in seconds. Built for curious climbers and boulderers.
01 / YOUR MEASUREMENTS
Example measurements. Enter yours to see your result.
REACH / HEIGHT1.033
Your proportions, visualised. Illustration only.
02 / EXAMPLE RESULT
+6.0cm
Arm span longer than height
Your arm span is 6.0 cm longer than your height.
Arm-span-to-height ratio1.033
A measurement, not a climbing grade. Your index describes proportions, not your potential.
KEEP YOUR NUMBERS. GO CLIMB.
03 / GET AN ACCURATE MEASUREMENT
Measure once. Check twice.
A wall, a tape measure and a friend are all you need. Measure twice before you compare.
Measure your arm span
Stretch both arms sideways at shoulder height. Keep your elbows and fingers straight, without straining. Ask a friend to measure from one middle fingertip to the other.
Check and calculate
Repeat both measurements in the same posture. If the numbers differ, measure again. Enter height and arm span in the same unit. Small measuring errors can change a small positive or negative result.
04 / THE NUMBERS EXPLAINED
What is your ape index?
Your ape index is a simple way to describe your body proportions: how your fingertip-to-fingertip arm span compares with your height. You may also see it called the arm-span-to-height ratio.
Climbers often compare these numbers out of curiosity. They are useful for understanding your proportions, but they do not predict a climbing grade or replace an assessment of your skills.
Arm span − height
186 cm − 180 cm = +6 cm
Arm span ÷ height
186 cm ÷ 180 cm ≈ 1.033
The difference changes with the unit; the ratio stays the same. A difference of 0 corresponds to a ratio of 1.
05 / GOOD QUESTIONS
Ape index FAQ
What is the ape index?
The ape index compares your arm span with your height. It is commonly expressed either as a difference (arm span minus height) or as a ratio (arm span divided by height). This calculator shows both.
How do I calculate my ape index?
Measure your height and your fingertip-to-fingertip arm span in the same unit. Subtract height from arm span for the difference. Divide arm span by height for the ratio. For example, 186 cm divided by 180 cm gives approximately 1.033.
What does a positive or negative ape index mean?
A positive difference means your arm span is longer than your height; a negative difference means it is shorter. In ratio form, those results are above or below 1. A difference of zero means the two measurements are equal.
Is there a good ape index for climbing?
There is no universal target in this calculator. The result describes your proportions and is not a score of your climbing ability. It does not account for technique, finger strength, mobility, experience or the demands of a particular climb.
Do I measure from my fingertips or wrists?
Measure from the tip of the middle finger on one hand to the tip of the middle finger on the other. Keep both arms horizontal at shoulder height and your fingers straight.
Can I use feet and inches?
Yes. Select Inches and enter total inches: multiply feet by 12, then add the remaining inches. For example, 5 ft 10 in is 70 inches. The calculator converts measurements when you switch units.
Does the calculator save my measurements?
The calculator itself processes your measurements in your browser and does not send them to APE13. Copying or downloading a result is optional. Other shop services are covered by the store’s privacy policy.