Comprehensive Calculator Guide
This calculator estimates your archery draw length from your arm span, so you can choose a bow and arrows that fit. A 178 cm span is about 70 inches; divided by 2.5 that gives a draw length of about 28 inches and an arrow of about 29.5 inches. Getting it right is the first step to shooting safely and accurately.
Measuring and why it matters
Stand against a wall with arms out level, palms forward, and have someone measure from middle fingertip to middle fingertip without stretching. Arm span is close to height for most people.
Compound bows are set to a draw length; too long and you overreach, too short and accuracy suffers. A recurve’s marked draw weight is measured at 28 inches. Arrows should be 1–2 inches longer than your draw.
How to Use
- Measure your arm span in centimetres.
- Enter it in the calculator.
- Press “Find my draw length” to see your draw length in inches and centimetres and a suggested arrow length.
Formula Used
Draw length (in) = arm span (in) ÷ 2.5 | Arrow ≈ draw length + 1–2 in
Practical Examples
- Example 1
- 178 cm = 70.1 in ÷ 2.5 = 28 in (71.2 cm); arrow about 29.5 in.
- Example 2
- 160 cm = 63 in ÷ 2.5 = 25.2 in (64 cm); arrow about 26.7 in.
Important Tips
- Start with a light bow and a coach.
- Try bows in the shop before buying.
- Always wear an arm guard and finger tab.
Common Mistakes to Avoid
- Buying a longer draw length thinking it’s more powerful.
- Using arrows shorter than your draw.
- Stretching the shoulders while measuring.
Frequently Asked Questions
- How do I find my draw length?
- Arm span in inches ÷ 2.5: a 70-inch span gives 28 inches.
- How long should arrows be?
- About 1–2 inches longer than your draw length.
- Compound vs recurve?
- The same rule works to start; on a recurve, actual draw weight changes with your draw length.