Free tool
Taekwondo Belt Size Calculator
Enter your waist measurement and get the belt length to look for, in centimeters and inches.
Reviewed by Daniel Reyes, 4th dan Kukkiwon, 18 years teaching | Last checked: October 20, 2026This calculator uses the common retail formula: waist x 2, plus 60 to 100 cm for the knot and tails. It gives a length range for a two-layer wrap. Always compare the result to the length in centimeters on the brand’s own size chart, because belt size numbers differ by brand.
Calculate your belt length
Enter your waist measurement to see the belt length you need.
Not sure how to measure? Wear your full uniform with the jacket tied, hold a soft cloth tape level around your waist, and keep it snug. Full steps are on our belt size chart page.
How the calculator works
The formula is waist times 2 for two layers around the body, plus 30 to 50 cm per side for the knot and tails. That gives a range because knots and tail lengths differ. The result is a starting point. It does not cover a one-wrap ITF belt, which needs a shorter length.
Next: tie it right
Once you have the belt, follow our belt tying guide.
Frequently asked questions
Does this work for kids?
Yes. Use the child’s waist measurement in their uniform.
What if I am between two sizes?
Size up. A belt that is a little long is easier to live with than one that is too short.
Does this work for ITF one-wrap belts?
No. It is built for the two-layer method.