A rash guard is one of the easiest fight gear gifts to get right — and one of the easiest to get wrong, because they're meant to fit completely differently to a normal t-shirt. This guide covers how a rash guard should fit, how to measure, and when to size up or down, for men's, women's and kids' sizing.
How a rash guard should fit
A rash guard is a compression garment. It should sit snug against the skin — think "second skin", not "loose gym shirt". You want no bunching at the armpits, no sagging at the waist, and no riding up when you move. But it should never restrict your breathing or cut into your shoulders; if it does, you've gone too tight.
The fit is what makes a rash guard work. A snug fit stops mat burn and friction, wicks sweat properly, and (for no-gi BJJ) gives your opponent less material to grip. A loose rash guard defeats the whole point.
How to measure for a rash guard
You only need two measurements:
- Chest — wrap a tape measure around the fullest part of your chest, under the armpits, keeping the tape level.
- Waist — measure around the natural waist (roughly at the navel), not your jeans waist.
Match your chest measurement to the brand's size chart. Chest is the measurement that matters most for a rash guard, because the shoulders and torso are where a compression fit either works or doesn't.
Men's rash guard sizing
Men's rash guards are cut straight through the torso and generally run true to size by chest measurement. If you're right on the line between two sizes, or you've got broad shoulders, size up — a slightly relaxed fit is more comfortable for training than a top that pinches across the back.
Women's rash guard sizing
Women's rash guards are more fitted through the waist and usually sized by bust and waist together. Go by the larger of your bust and waist measurements against the chart, and size up if you're between sizes or prefer a touch more room through the hips.
Kids' rash guard sizing
Kids' rash guards are usually sized by age, but kids grow fast — if you're buying for a child who's tall for their age or between sizes, go one up so they get more than a few months out of it. For a gift, err on the side of roomier rather than too tight.
Short sleeve vs long sleeve
Long sleeve is the standard for BJJ and no-gi grappling — it protects your arms from mat burn and gives your opponent less to grip. Short sleeve runs cooler and is the better pick for striking, Muay Thai and general training. If you're not sure what they train, long sleeve is the safer all-round choice.
Buying a rash guard as a gift
Rash guards are one of the best "size-safe" fight gear gifts because a slightly roomier fit is still perfectly wearable — unlike gloves (weight) or a gi (measurements). If you don't know the person's exact size, size up. You can't go far wrong.
Shop rash guards
Browse the full range — men's, women's and kids' — at MMA Fight Store:
Related Reading
• The Ultimate Fight Gear Gift Guide — more size-safe gift ideas
• BJJ Gear Guide: Gi vs No-Gi — what you actually need
• What Size BJJ Gi Do I Need? — gi sizing explained
