SWIM BRIEF SIZE GUIDE
Find your size in 30 seconds. Our swim briefs are cut to fit snug, so getting the size right makes all the difference. Here’s everything you need, from the chart to the at-home fit test.
The quick answer
Measure a brief you already love (laid flat, straight across the waistband) and match it to the half-waist row below.
Between sizes? Size down. Swimwear relaxes slightly in the water.
Got it wrong? Unworn items can be returned within 30 days.
Mandate Swim Brief: Size Chart (cm)
Applies to the Mandate Swim Brief, the Swim Brief Duo and the Swim Brief Trio. All measurements are taken on the garment, laid flat, in centimeters.
| Measurement | How it's measured | S | M | L |
|---|---|---|---|---|
| Half-waist | Waistband, side to side, laid flat | 33 cm | 36 cm | 39 cm |
| Waistband height | Top to bottom of the waistband | 3.5 cm | 3.5 cm | 3.5 cm |
| Front rise | Bottom of waistband to bottom of front | 25 cm | 26 cm | 27 cm |
| Back rise | Bottom of waistband to bottom of back | 27 cm | 28 cm | 29 cm |
| Bottom width | Crotch, side to side | 9.5 cm | 9.5 cm | 9.5 cm |
| Side seam | Side seam, including waistband | 9.5 cm | 10 cm | 10.5 cm |
Swipe the table sideways to see every size.
All measurements are taken on the garment, laid flat, in centimeters. Half-waist in inches: S 13.0 in, M 14.2 in, L 15.4 in. Between sizes? Size down.
How to measure (the garment-to-garment method)
This is the most accurate way to choose, because it already reflects how you like a brief to fit.
Pick a brief or pair of underwear that already fits you the way you like.
Lay it flat on a table, front facing up, without stretching it.
Measure straight across the waistband, edge to edge. That’s your half-waist.
Match it to the chart. Choose the Mandate size with the closest half-waist. If you’re exactly between two sizes, go for the smaller one.
How a swim brief should fit
Snug, not tight. A good swim brief stays put when you move and leaves no marks.
Waistband: lies flat all the way round. Two fingers slide under comfortably; a whole hand means size down.
Front: the contoured pouch should hold and shape, not press or sag.
Leg openings: follow the crease at the top of your thigh. No red lines, no gaps.
Seat: smooth across the glutes, with no bunching or riding up.
The 30-second test
Try it on dry, over underwear, then bend forward, squat, lift each knee to your chest, and sit down. If nothing rolls, gapes or needs adjusting, it fits.
Want the full breakdown? Read How Should Men’s Swim Briefs Fit? The 30-Second Test (on our Journal).
Too small or too big?
| Too small | Too big |
|---|---|
| Red marks on your skin when you take it off | It shifts when you move or climb out of the pool |
| Waistband rolls down | Front looks baggy rather than shaped |
| Leg openings cut in when you walk | Leg openings gape when you sit |
| Fabric looks strained when stretched | You keep hitching it up |
Mandate Signature Boxer Brief: Sizing
For the Mandate Signature Boxer Brief. Sizes S to XL.
The Signature Boxer Brief comes in S, M, L and XL with a smooth, supportive everyday fit. Not sure which size? Email support@mandate.store with your usual underwear size and we’ll help you choose.
Fit notes: supportive contour, waistband designed to stay flat and not roll, mid-length leg for a clean line under pants.
Sizing FAQ
Should I size up or down in swim briefs?
If you’re between sizes, size down. Swim briefs are meant to fit snug and relax slightly in the water.
Are the bundle briefs the same size as the single brief?
Yes. The Duo and Trio are the same Mandate Swim Brief, so use the same chart. You choose one size for the whole bundle.
Do you make XL in swim briefs?
The Mandate Swim Brief currently comes in S, M and L. The Signature Boxer Brief comes in S to XL.
What if my size isn’t right?
Unworn items can be returned within 30 days. Try your brief on dry, over underwear, so it stays unworn while you check the fit.
Still unsure?
Email support@mandate.store with the half-waist measurement of a brief you like, and we’ll tell you which size to choose.
Ready? Shop the Mandate Swim Brief, red or black, $39.99. Duo: 2 for $69.98. Trio: 3 for $99.97. Signature Boxer Brief: $29.99.