Trusted calculators for grapplers

Know your numbers before you step on the mat.

Weight classes, points, weight cuts, gi sizing, recovery — the numbers every BJJ practitioner Googles mid-week, worked out from cited sources instead of forum guesses.

Every result links to the IBJJF rule or sports-medicine source behind it. Nothing here is made up to fill a box.

IBJJF-SourcedSources CitedBlack-Belt Review Pending
Live demo — IBJJF Weight Class Finder
Why you can trust the numbers

Built like a calculator, reviewed like methodology

A wrong weight class or a reckless cut costs someone a medal or their health. So every tool is sourced, shown, and held to a review standard before we call it done.

Straight from the rule book

Divisions, points and brackets follow the current IBJJF rules — with the gi-on weigh-in convention competitors actually face.

Every number is sourced

Open the methodology page and you can trace each calculator to the rule, study, or equation it runs on. No black boxes.

Practitioner review before launch

Health and rules tools are written for black-belt and sports-medicine review. Until that’s signed off, each one says so plainly.

Honest about estimates

Recovery, belt timelines and calories are ranges, not promises. We label what’s a rule versus what’s an educated estimate.

Why BJJMath?

No serious calculator hub for grappling existed. So we built one.

Search any of these questions today and you get a PT clinic blog, a five-year-old Reddit thread, or a forum argument. We wanted one place that does the math, shows its work, and earns the community’s trust the hard way.

10calculators at launch, each tied to a source
1methodology page documenting every formula
0numbers invented to fill a gap in the data
100%free to use — funded by relevant gear links, not ads
Free download

The Tournament Prep Checklist

One page: making weight safely, registration deadlines, what to pack, and a warm-up that won’t gas you before bracket one. Join the list and we’ll send it over.

No spam. Unsubscribe anytime. We use Beehiiv to send it.

BJJMathPREP
CHECKLIST
  • Weigh-in math, double-checked
  • Safe cut timeline
  • Mat-side warm-up
  • Packing & rules recap