BJJ Gi Fabric Weights: 380 vs 450 vs 500 GSM

BJJ Gi fabric weight is measured in GSM (grams per square metre) — the density of the jacket's pearl-weave cotton. Gimakx makes three weights, and the right one depends on how, and how often, you train. A 380 GSM Gi (GiPro Aerotough) is lightweight and breathable — best for beginners, kids, fast rollers, hot climates, and competitors cutting weight. A 450 GSM Gi (GiPro Fortitude) is the all-round default: durable enough for daily intensive training yet still mobile, which is why it's the most common weight on competition mats. A 500 GSM Gi (GiPro Monolith) is the heaviest and most durable, built to last years of hard rounds and harder for opponents to grip — favoured by instructors and masters. All three sit inside the IBJJF's legal 380–650 GSM range.

After years of producing countless Gis, we wrote this guide to clear up what fabric weight actually means for the way a BJJ Kimono feels, performs, and lasts. The numbers — 380, 450, 500 — refer to grams per square metre of the jacket fabric. A higher number means a denser, heavier weave; a lower number means a lighter, more breathable one. Below is how the three Gimakx weights compare, written from the factory floor.

Quick comparison: 380 vs 450 vs 500 GSM

*Lifespan reflects what customers report with regular care, and depends on how often you train and how you wash. Denser, heavier weaves generally take more abuse before they show wear, so at the same training frequency a 450 GSM Gi typically outlasts a 380 GSM one.

What does GSM mean on a BJJ Gi?

GSM stands for grams per square metre and measures the density of the Gi jacket's fabric — almost always pearl weave cotton in modern Gis. It does not directly measure thickness or total Gi weight; it measures how much cotton is packed into the weave. A higher GSM means more thread, a tighter weave, more durability and grip resistance, but also more warmth and weight. A lower GSM means a more open, breathable weave that moves easily and dries fast. Trousers are quoted separately (our GiPro pants use a 270 GSM ripstop), so "Gi weight" in a spec almost always refers to the jacket.

380 GSM — GiPro Aerotough (lightweight)

This is our least dense fabric, which makes it the smart choice for beginners and kids. It's a lightweight cotton that provides both mobility and breathability while still holding to the highest quality standards — hence the name Aerotough. It's commonly chosen by younger and faster athletes who prioritise speed and range of motion.

The low density of this 380 GSM pearl weave lets the fabric stay flexible — the cloth moves with your body rather than fighting it. The trade-off? With regular maintenance and care, customers report keeping these for 1–2 years. Worth noting: 380 GSM now sits exactly at the minimum jacket weight the IBJJF has permitted in competition since its 2024 rule change, so the Aerotough stays tournament-legal while shaving precious grams at the weigh-in. The open weave breathes well in hot, humid gyms and dries quickly after washing, which makes it a favourite for summer training and travel. Although it's our thinnest fabric, a good pearl weave holds up far better than its light feel suggests.

450 GSM — GiPro Fortitude (mid-weight)

For intermediate and advanced players who train intensely, our preferred weight is a resilient 450 GSM pearl weave cotton. GiPro Fortitude is the blend we recommend for long hours on the mat because of its strength and increased density — you can push through demanding sessions without feeling armoured. After a few rounds, give it roughly 4–8 weeks of use for the fabric to soften to its best feel.

This is why 450 GSM has become the default competition weight you'll see most often on the mats. It sits comfortably inside the IBJJF's legal 380–650 GSM window and hits the sweet spot between the mobility of a lighter Gi and the toughness of a heavier one. Worn several times a week, a Fortitude Gi will typically serve you well for two to three years. To protect that lifespan, wash it in cold water and hang it to dry rather than tumble drying — this limits shrinkage and keeps the weave strong.

500 GSM — GiPro Monolith (heavyweight)

A Gi made from highly dense 500 GSM pearl weave cotton is built to be the most resistant — hence the name Monolith. If you're a grand master or sensei, Monolith is the best choice. Higher thread counts make for the denser weave.

Beyond sheer durability, that density gives the Monolith a real edge in grip fighting: the tighter, heavier cloth is simply harder for an opponent to grab and control. It's built to outlast lighter Gis through years of hard rounds, yet at 500 GSM it still sits under the IBJJF's 650 GSM ceiling and remains competition-legal. The trade-offs are real — it runs warmer, dries more slowly, and adds more to the scale at the weigh-in — so it best suits practitioners who prize longevity over cutting weight.

Which BJJ Gi weight should you choose?

Match the weight to how you train, not just to durability on paper:

Choose 380 GSM (Aerotough) if you're a beginner or kid, you roll fast and value range of motion, you train in a hot or humid climate, or you want the lightest tournament-legal option at the weigh-in.

Choose 450 GSM (Fortitude) if you train hard several times a week and want one Gi that does everything — the balanced, most popular competition weight for intermediate to advanced players.

Choose 500 GSM (Monolith) if you're an instructor or master, you want maximum durability over many years, and you want a tougher, harder-to-grip jacket — and you don't mind extra warmth and weight.

How to care for your Gi (all weights)

The single biggest factor in how long any Gi lasts is washing. Wash in cold water, hang to dry rather than tumble drying, and avoid harsh bleach on coloured Gis. Cold washing and air drying limit shrinkage and protect the pearl weave — heavier fabrics like 500 GSM simply need more drying time. A small amount of natural shrinkage (roughly 1–3%) can occur on the first few washes even with pre-shrunk cotton, so factor that into sizing.

Frequently asked questions