The sizing conversation is where most first-time buyers go wrong. BJJ belt sizing uses a letter system: A0, A1, A2, A3, A4 for adults, plus kids sizes that run separately under a different scale. The letter corresponds to body type and height, not rank. A practitioner around 180 cm training at 80 kg generally fits an A2, but the right size also depends on how you tie. A thick double-knot pulls 15 to 20 centimeters more length than a flat single wrap. If you order based on waist measurement alone and don't account for your knot method, expect the belt to hang awkwardly or fall short on one side.
Cotton belts are the standard. They start stiff, soften over months of training, and develop that worn-in texture experienced practitioners recognize. Cotton doesn't migrate easily once knotted, which matters during positional drilling when you don't want the knot creeping. Synthetic blends, usually polyester-based, resist fraying better and hold color longer. A white belt in polyester blend will stay white through many washes where cotton yellows faster. The trade-off is that poly belts can be slippery when new, and the knot loosens more readily under grappling pressure. Neither material is wrong. It comes down to which failure mode bothers you more in practice.
The black tip at the end of an adult belt isn't decorative. It marks the belt as belonging to the adult rank system under IBJJF and most major association standards. Kids belts, which run through a separate color progression depending on the academy or federation, use a colored tip or no tip to distinguish them. At IBJJF-affiliated events, check-in staff verify belt specification alongside gi patches and competitor registration. Showing up with the wrong tip type for the division you registered in creates a problem at the table, not on the mat.
Belt width is the regulation detail that almost no retail page explains. IBJJF rules specify a minimum belt width of approximately 4 to 5 centimeters. Some beginner kits include thinner belts in the approximate color of the buyer's rank. These don't pass competition inspection. If you're buying specifically for a sanctioned event, confirm the width against the ruleset of the organization before purchasing. For open local tournaments, enforcement varies and tends to be looser.
Honestly, buying a belt before asking your academy is the most common avoidable mistake. Many gyms in the US and UK have a preferred supplier, or they source belts directly as part of a uniform policy. Some academies follow stripe systems tied to specific materials or color coding that differ from the IBJJF standard. Buying independently works fine once you know what your gym uses. Getting there first saves a return.
Belts wear out. A cotton belt used four to five days a week will typically show fraying at the edges within six to twelve months. The knot area degrades first because it takes the most repeated stress. Color fading is normal and doesn't affect function. Visible fraying is cosmetic during training but may cause questions at competition check-in if the belt is clearly deteriorated. Replacing a worn belt doesn't reset rank. The stripes or color are what matter, not the physical belt itself.
Washing is where cotton belts get damaged unnecessarily. Machine washing in warm water is the standard approach. Hot cycles shrink cotton belts, sometimes enough to affect the useful length by several centimeters. Air drying extends the belt's life more than most buyers expect. A belt balled up damp inside a gym bag after training will pick up odors much faster than one that gets hung up and dried immediately after class.
The trade-off between cotton and synthetic is real but smaller than the marketing around it suggests. Heavy trainers who wash frequently tend to prefer synthetic blends for color retention and fraying resistance. Practitioners who prioritize feel and traditional textile prefer cotton. Neither is more legitimate by any governing body standard. The belt does one functional job on the mat: it holds the gi top together and signals rank. Every other consideration is preference.
