Data-backed tools to plan your jiu-jitsu journey — built and pressure-tested by a physician purple belt, not pulled from gym folklore. Free, no sign-up to use.
BJJ Black Belt Calculator — Project your personal black belt date from how you actually train. Calibrated to survey data from 1,948 practitioners — the real average is 13.3 years, not 10.
Weight Cut Calculator — Plan a safe cut to your division — fat-loss vs water-cut budget, the water-loading schedule, a rehydration protocol, and a hard stop before you hurt your performance or your health.
Gi Size Calculator — Your gi size in every major brand, from charts verified at the source. An A2 is not a size: Fuji's ends at 170 lb where Tatami's begins. Includes a shrink forecast and the current 2 cm IBJJF check.
Jiu-Jitsu Style Quiz (coming soon) — Answer a handful of questions and find the game that fits your body and brain — guard player, pressure passer, leg locker, or scrambler.