Kids
Is BJJ good for kids? Benefits, age, and what to expect
Is BJJ good for kids? Yes — it builds discipline, confidence, fitness, and real self-defense, with low striking risk. What age to start and what to expect.
Field notes
The BJJMath blog
Practical, source-backed writing on the things the calculators touch: competition rules, safe weight management, and gear that actually fits.
Start here
New to the site? Try the Getting Started hub, the BJJ Basics hub, the Weight Cutting hub, or the IBJJF & ADCC data reference.
Kids
The BJJ belt system for kids, explained
The kids BJJ belt system: white, grey, yellow, orange, green (ages 4–15), how sub-ranks and stripes work, and the transition to adult belts at 16.
Beginners
Starting BJJ as a woman: what to know
Starting BJJ as a woman: what to expect, common concerns about training with men, gear and gi sizing, and why leverage-based grappling suits women so well.
Beginners
BJJ for MMA: how grappling fits into mixed martial arts
BJJ for MMA: why it's a foundational skill, how sport BJJ differs from MMA grappling, and how it combines with wrestling and striking.
Beginners
BJJ vs Muay Thai: grappling vs striking
BJJ vs Muay Thai: grappling versus striking. How they differ, which is better for self-defense and fitness, and why the two together are so complete.
Beginners
BJJ submissions explained: chokes and joint locks
BJJ submissions explained: the two types — chokes and joint locks — how they work, common examples, why you tap, and which suit beginners.
Beginners
How to choose a BJJ gym
How to choose a BJJ gym: what to look for in instructors, culture, safety, and cleanliness — plus red flags to avoid and trial-class questions.
Beginners
What to expect at your first BJJ class
What to expect at your first BJJ class: what to wear and bring, the warm-up, drilling, whether you'll spar, and how to handle feeling lost.
Gear
Best BJJ rashguards: a buying guide
A BJJ rashguard buying guide: what to look for in material, fit, and seams, long vs short sleeve, competition rules, and how to choose one that lasts.
Health
What to eat before and after BJJ training
What to eat before and after BJJ: fuel for energy, food for recovery, timing, hydration, and whether to train fasted. A practical guide.
Health
How dangerous is BJJ? An honest look at the risks
How dangerous is BJJ? An honest look: most injuries are minor sprains and strains, serious injury is uncommon, and smart habits cut the risk.
Health
Supplements for BJJ: what's worth it?
Supplements for BJJ: which are actually worth it — protein, creatine, caffeine, and a few others — and which to skip. Evidence-based, food-first guidance.
Health
The most common BJJ injuries and how to avoid them
The most common BJJ injuries — fingers, knees, skin infections — what the research shows and practical, evidence-based ways to reduce your risk.
Beginners
Is BJJ good for self-defense?
Is BJJ good for self-defense? Yes for a single unarmed attacker — with real limits against weapons, multiple attackers, and strikes. A balanced look.
Beginners
BJJ vs Judo: which should you train?
BJJ vs Judo: judo focuses on throws and standing grappling, BJJ on ground fighting and submissions. Their shared roots, key differences, and how to choose.
Beginners
BJJ vs Wrestling: how they compare
BJJ vs Wrestling: wrestling focuses on takedowns and top control, BJJ on submissions and guard. Their differences and why wrestlers thrive in BJJ.
Beginners
What is Brazilian Jiu-Jitsu? A beginner's guide
What is Brazilian Jiu-Jitsu? A grappling martial art where leverage lets a smaller person control and submit a larger one — history and how it works.
Beginners
BJJ positions explained: a beginner's map
BJJ positions explained: guard, side control, mount, back control and more, from worst to best — the hierarchy that makes ground fighting click.
Gear
Do you need a mouthguard, headgear, and knee pads for BJJ?
BJJ protective gear explained: mouthguards, ear guards, knee pads, and more — what's essential, what's optional, and what's not allowed in competition.
Beginners
Mat etiquette: the unwritten rules of BJJ
BJJ mat etiquette: the unwritten rules of hygiene, tapping, rolling safely, and respect. What every beginner should know before their first class.
Gear
How to size a BJJ gi you can't try on
How to size a BJJ gi you can't try on: a repeatable method using the A-scale, brand charts, your build, and shrinkage — so ordering online isn't a gamble.
Training
Estimate your 1RM without maxing out (for grapplers)
Estimate your one-rep max without maxing out: why grapplers shouldn't test a true max, the Epley and Brzycki formulas, and how to train off percentages.
Competition
What weight class am I in for BJJ? (IBJJF + ADCC)
What weight class am I in for BJJ? How divisions work, why IBJJF includes the gi, the full IBJJF and ADCC divisions, and where people miscalculate.
Training
Why haven't I been promoted? BJJ belt timelines explained
Why haven't I been promoted in BJJ? It's usually normal. Typical time per belt, the IBJJF minimums, what drives your pace, and why chasing belts backfires.
Training
Are you overtraining in BJJ? Signs and how to read your load
Are you overtraining in BJJ? The warning signs — fatigue, nagging injuries, stalled progress — and how to balance training load against recovery.
Health
How much water do you need for BJJ?
How much water do you need for BJJ? A daily baseline plus your sweat losses. How to measure your sweat rate, why you cramp, and stay hydrated.
Health
Gi vs no-gi: which is better for weight loss?
Gi vs no-gi for weight loss: which burns more calories? The honest answer — the difference is small, and consistency matters far more than either.
Competition
IBJJF vs ADCC: rules and weigh-ins compared
IBJJF vs ADCC: gi vs no-gi, points vs submissions, same-day vs day-before weigh-ins, and legal leg locks. A clear comparison to pick your event.
Gear
Home mats vs gym-only: the real cost of a garage BJJ setup
How much does a home BJJ mat setup cost? Mat types, cost per square foot, how much space you need, and whether a garage dojo is worth it.
Competition
The best way to cut weight for a same-day IBJJF weigh-in
The best way to cut weight for a same-day IBJJF weigh-in: cut gradually, keep final-days water small, remember the gi counts, and when to move up.
Competition
Reddit: how much weight can you cut for a BJJ tournament?
How much weight can you cut for a BJJ tournament? The r/bjj take: cut slowly, skip big water cuts for same-day IBJJF weigh-ins, or move up a division.
Gear
Reddit BJJ gi sizing questions, answered (A1 vs A2 vs A3)
BJJ gi sizing answered: how A-sizing works, A1 vs A2 vs A3, whether to size up for shrinkage, and the between-sizes fixes r/bjj asks about most.
Health
Does BJJ help you lose weight? What Reddit's transformations show
Does BJJ help you lose weight? Yes — it burns serious calories and builds consistency, but diet still decides. What r/bjj weight-loss threads show.
Competition
Reddit's most-asked BJJ competition questions, answered
First BJJ competition? The questions r/bjj asks most, answered: scoring, weigh-ins, match length, weight and age divisions, and what to bring on the day.
Health
How many calories does BJJ actually burn?
How many calories does BJJ burn? Often 400–800+ per hour by weight and intensity. The MET math, why your watch is wrong, and how to estimate yours.
Health
How much protein do you really need for BJJ?
How much protein for BJJ? Around 1.6–2.2 g per kg of bodyweight a day supports recovery. Why it matters, cutting vs building, and whether you need shakes.
Gear
Is an expensive BJJ gi worth it?
Is a $150+ BJJ gi worth it, or is a budget gi fine? What your money actually buys, when premium pays off, and why fit beats brand every time.
Beginners
How much does BJJ cost per month?
How much does BJJ cost? A transparent breakdown of monthly membership, first-year gear, and hidden costs — plus where beginners overspend and how to save.
Gear
Cheap vs expensive BJJ gi: what you're paying for
Cheap vs expensive BJJ gi: what the price difference buys — fabric, weave, GSM, durability and competition weight — and which tier is right for you.
Gear
How many BJJ gis do you actually need?
How many BJJ gis do you need? It comes down to how often you train and how long a gi takes to dry. A simple guide to sizing your gi rotation.
Gear
Do you need a lightweight competition gi?
Is a lightweight competition gi worth it? IBJJF weighs you in your gi, so a lighter gi saves grams — here's when it matters and when it doesn't.
Gear
What Reddit says about expensive BJJ gis
Is an expensive BJJ gi worth it? The r/bjj consensus: fit beats brand, budget gis are fine, premium buys durability and looks — not skill.
Competition
BJJ Weight Cutting, According to Reddit
What r/bjj says about cutting weight for a tournament: skip big water cuts for same-day IBJJF weigh-ins and pick a division near your walking weight.
Gear
The Best BJJ Gi, According to Reddit
The gis r/bjj recommends most: Sanabul and Elite Sports for value; Tatami, Hyperfly, Kingz mid-range; Origin and Shoyoroll premium. Fit beats brand.
Training
How Long to Blue Belt, According to r/bjj
How long does a BJJ blue belt take? The r/bjj consensus is about 1.5–3 years of consistent training — and the real advice: stop chasing belts.
Training
Am I too old to start BJJ?
Too old for BJJ? An honest answer on starting jiu-jitsu in your 30s, 40s or beyond — what changes with age, what doesn't, and how to train smart.
Training
Why am I not improving at BJJ?
Feeling stuck in jiu-jitsu? Why plateaus happen, why you're probably better than you feel, and the concrete things that actually get you progressing again.
Beginners
Surviving your first months as a white belt
Getting smashed every round as a new white belt? That's normal. How to survive, what to focus on, and how to roll with bigger people without getting hurt.
Health
Cauliflower ear: prevention and what to do
What causes cauliflower ear in BJJ, how to prevent it, and what to do at the first sign of swelling. Educational, not medical advice.
Training
Do you need to lift weights for BJJ?
Does strength training help your jiu-jitsu or just make you a stronger white belt? The honest take, plus how to lift without wrecking recovery.
Training
Why do I gas out in BJJ?
Gassing out after one round? Why it happens (mostly it's not your cardio) and the technique, breathing and conditioning fixes that build a real gas tank.
Competition
IBJJF rules, explained without the jargon
A plain-English guide to IBJJF rules: how points are scored, how weight and age divisions work, and the gi weigh-in detail that catches people out.
Competition
How to cut weight for a BJJ tournament — safely
How to make weight for a BJJ tournament safely: sensible weekly loss rates, what to avoid, and when to just compete a division up instead.
Gear
Choosing the right BJJ gi for your size
A practical guide to BJJ gi sizing: how A-sizes map to height and weight, why brands differ, and how shrinkage changes the math.
Competition
IBJJF weight classes, explained simply
A clear guide to IBJJF adult gi weight classes, the gi-on weigh-in rule that trips people up, and how to find the division you actually belong in.
Competition
How IBJJF points actually work
Takedown 2, pass 3, mount 4 — the IBJJF points system explained with the control rule, advantages, and how matches are decided when nobody taps.
Competition
IBJJF age divisions and Masters, explained
How IBJJF age divisions work: the competition-year rule, the Juvenile and Masters 1–7 brackets, and why you can compete down but not up.
Competition
Your first BJJ competition: a complete prep guide
Everything for your first BJJ tournament: picking a division, making weight, what to pack, how weigh-ins and brackets work, and what to expect on the day.
Competition
How IBJJF weigh-ins work (and how to avoid a DQ)
How IBJJF weigh-ins actually work: same-day timing, weighing in your gi, what happens if you miss weight, and how to avoid an avoidable disqualification.
Gear
How much does a BJJ gi weigh?
How much a BJJ gi weighs by weave — pearl weave, double weave, lightweight comp gis — and why it matters for making weight at IBJJF weigh-ins.
Gear
How to shrink (or stop shrinking) a BJJ gi
How BJJ gi shrinkage works: how to shrink a gi that's too big, and how to stop one shrinking when it already fits, by fabric and wash method.
Gear
How to wash a BJJ gi the right way
How to wash a BJJ gi to keep it clean, prevent shrinkage and skin infections, and make it last: temperature, drying, smell, and mat-hygiene basics.
Gear
How to pick your first BJJ gi
How to choose your first BJJ gi: what size to get, what to ignore, IBJJF-legal basics, and the qualities that matter for a beginner's kimono.
Gear
BJJ gear checklist for your first class
What you need for your first BJJ class and what you don't: gi, rashguard, mouthguard, flip-flops, plus the hygiene basics for beginners.
Gear
Gi vs no-gi: which should you start with?
Gi vs no-gi BJJ for beginners: the real differences in pace, grips, rules and gear, and an honest answer on which one to start with.
Health
How many calories should a grappler eat?
How to estimate calories for BJJ using the Mifflin–St Jeor equation, set protein and macros for grappling, and fuel training without crash dieting.
Health
How long does it take to get a BJJ black belt?
How long it really takes to earn a BJJ black belt, the IBJJF minimum time-in-grade rules, and what actually drives how fast you progress.
Health
BJJ belt ranks, explained in order
The BJJ belt order for adults and kids, what each rank means, the stripe system, and how IBJJF time-in-grade rules fit in — a plain guide for beginners.
Health
Returning to BJJ after injury or time off
How to return to BJJ safely after injury or a layoff: easing back in, protecting the injured area, and when to stay off the mat.
Health
BJJ skin infections: prevention and when to stay off the mat
The common BJJ skin infections — ringworm, staph, impetigo, herpes gladiatorum — how to prevent them, and the rule on when to stay off the mat.
Health
How often should you train BJJ?
How many times a week to train BJJ for steady progress without burning out or getting hurt, plus how to read your recovery and the signs of overtraining.