I got my first white belt with my first gi. The belt was a good fit (I guess) and I did not pay much attention to the length of it. The gi was Tatami (size A2) so probably the belt was also A2.
I got another white belt with Ippon gi, A2 again. As our BTT gis come without belts then I left it on the hanger in the gym so that someone else could use it. And, it found its new owner quickly. The third one I got with Progress Academy gi, A1L this time.
Right belt size
IBJJF uniform requirements state that the belt should be 4 to 5 cm wide. Once tied in a double knot, each end of the belt should hang 20 to 30 cm in length. Though, they do not specify how they measure this 20 to 30 cm.
From the Venum website, I found a formula how to calculate the correct BJJ belt length: waist size * 2 + 100 cm. So in my case, it should be 80 cm * 2 + 100 cm = 260 cm.
Not sure if the formula works 100% of the time but it at least gives some kind of indication. For me, to be honest, 275-280 cm feels much better than 260 cm. Please check real belt lengths (in cm) when buying a belt. For example some belt lengths and sizes from my experience:
Tatami Adult BJJ Rank Belt – A0 – 265 cm, 4cm wide (this is what I wear, feels short but is OK)
Tatami Deluxe BJJ Belt – A1 – 264 cm (same brand but A1 is shorter(!) than A0)
Ippon Gear Adult BJJ Belt – A1 – 260 cm
Progress (came with the Academy gi) – A1L – 254 cm
Wacoku BJJ belt – A2 – 260 cm (but it is also quite wide and thick)
Manto Label belt – A2 – 282 cm – have it, a bit too long for me (waist ~80 cm) but good because it does not come loose
Scramble Kihon A2 – 290 cm
As you can see, the belt sizing is a mess. Progress A1L belt is clearly too short for me (I tried) even though the gi fits. Wacoku seems to be the correct length but as it is quite wide (4.5 cm or more) and thick then the knot will be bulky and falls off easily. Even though I wear mostly A2 gis then the Manto A2 belt (282 cm) is way too long for me (and it is a very-low quality belt).
For some reason, Tatami and Manto do not provide belt lengths on their product pages. Width is also rarely shown for all producers.
Tatami BJJ belt lengths
I asked Tatami customer support where could I find their belt sizing guide and they sent me the lenghts of all their models. Maybe useful for somebody so I thought I share these.
Tatami Adult Belt
A0 – 265 – 270 cm
A1 – 275 cm
A2 – 283 cm
A3 – 293 cm
A4 – 308 cm
A5 – 320 cm
Tatami Ladies Belt
F1 – 250 cm
F2 – 265 cm
F3 – 280 cm
F4 – 290 cm
Tatami Deluxe Belt
A1 – 264 cm
A2 – 288 cm
A3 – 313 cm
A4 – 342 cm