Sweaty Betty Sizing
Sweaty Betty is a British activewear brand running sizes 4 to 22 — one of the most inclusive size ranges in the premium activewear category. Their sizing is consistent and true to size across most of the range, but the compression and stretch characteristics of the fabric mean that first impressions of fit are not always the final fit.
This guide covers leggings, tops, and sports bras separately, because the fit intention is different for each. Leggings are designed to be fitted. Tops are often cut with more ease. Sports bras require two measurements to get right.
1 | Size Range: 4 to 22
Sweaty Betty uses UK lettered sizes (XS, S, M, L, XL, 1X, 2X, 3X) which correspond to UK numbered sizes (8, 10, 12, 14, 16, 18, 20, 22). Some styles also show the corresponding US size, which is 4 sizes higher than UK (UK 8 = US 4).
| UK Size | US Size | Letter Size | Bust (cm) | Waist (cm) | Hips (cm) |
|---|---|---|---|---|---|
| 4 | 0 | XXS | 77–80 | 60–63 | 84–87 |
| 6 | 2 | XS | 81–84 | 64–67 | 88–91 |
| 8 | 4 | S | 85–88 | 68–71 | 92–95 |
| 10 | 6 | S/M | 89–92 | 72–75 | 96–99 |
| 12 | 8 | M | 93–96 | 76–79 | 100–103 |
| 14 | 10 | L | 97–100 | 80–83 | 104–107 |
| 16 | 12 | XL | 101–104 | 84–87 | 108–111 |
| 18 | 14 | 1X | 108–113 | 91–96 | 115–120 |
| 20 | 16 | 2X | 114–119 | 97–102 | 121–126 |
| 22 | 18 | 3X | 120–125 | 103–108 | 127–132 |
Between Sizes?
For leggings and sports bras: go with the size that matches your hip or bust measurement (whichever is larger). For tops: if you are between sizes, consider whether you prefer a fitted or relaxed feel — go down for fitted, up for relaxed.
2 | Leggings: Buy Your Normal Size
Sweaty Betty leggings use a four-way stretch fabric designed to move with the body. The construction is intentionally compressive — leggings are meant to feel snug, support the muscles, and hold their shape during activity.
Leggings Sizing Rules
- Buy your normal size — the fabric is designed to fit your body, not to be loose
- The waistband will feel firm initially and will soften after the first few wears and washes
- Leg length is cut for a model of approximately 5'9" (175cm) — petite customers may want a crop style
- Do not size up hoping for a looser fit — the fabric will not sit correctly if oversized
- If your hips are at the top of one size, go up rather than down
The most common sizing question with Sweaty Betty leggings is: "they feel tight — should I size up?" The honest answer: not unless you are between sizes and your hip or waist measurement puts you in the next size. The compression is intentional and is part of how the leggings perform and look.
3 | Tops: Consider Sizing Down
Unlike leggings, Sweaty Betty tops — including training tops, hoodies, and jackets — are often cut with more ease than a typical fitted activewear top. This is intentional for tops designed to layer or be worn casually post-workout.
Fitted Training Tops & Bra Tanks
True to size or consider sizing down if you prefer a close fit. These are cut close to the body with stretch fabric. If you are between sizes, go down for a fitted feel.
Relaxed Hoodies & Oversized Tops
True to size. These are cut with intentional volume. Do not size down expecting a fitted look — the relaxed silhouette is the design intent.
Zip-Up Jackets & Running Tops
True to size. Designed to layer over a sports bra or base layer. If you plan to wear a thick base layer underneath, go up one size.
Crop Tops & Longline Tops
True to size. Crop length is cut for a standard 5'6"–5'8" (168–173cm) height. Taller customers may find crop tops sit higher than expected.
4 | Sports Bras: Band + Cup
Sweaty Betty sports bras are available in two formats: size-specific (with band and cup sizing, e.g. 32B–38DD) and letter-sized (XS–XL, for lower-impact styles). Getting the right band size is more important than cup size for fit and support.
How to Measure for a Sports Bra
- Band size: Measure around your ribcage, directly under your bust. Round to the nearest even number. Add 4 if the result is odd (e.g. 29" + 4 = 33" → round to 34 band).
- Cup size: Measure around the fullest point of your bust. Subtract your band measurement. Each inch = one cup size (1" = A, 2" = B, 3" = C, etc.).
- The band should feel firm — you should not be able to pull it more than 2 fingers away from your body.
| Letter Size | Band Sizes | Cup Range |
|---|---|---|
| XS | 28–30 | A–B |
| S | 30–32 | A–C |
| M | 32–34 | B–D |
| L | 34–36 | C–DD |
| XL | 36–38 | D–E |
Band vs Cup Priority
If the band fits well but the cup is slightly too small, size up in the letter size. If the band is the right fit, do not go to a larger band size just for more cup volume — this compromises support. For high-impact activity (running, HIIT), choose the size that gives the firmest band fit.
5 | Power Legging vs Super Sculpt: Fit Differences
Power Legging
Sweaty Betty's signature high-performance legging. Thick, dense fabric with strong compression — designed for running, HIIT, and high-intensity training. Feels firm and structured. Waistband is high and stays up during dynamic movement. Buy your normal size.
Super Sculpt Legging
Lighter, softer fabric with a sculpting compression construction. Designed for yoga, Pilates, barre, and lower-intensity activity. Adapts to the body more quickly than the Power Legging. Still fitted, but with a softer feel. Buy your normal size.
Both leggings use the same size chart (section 1 above) and both are designed to be bought in your normal size. The key difference is the fabric weight and the type of activity they are designed for, not the sizing approach.
Customers who are new to Sweaty Betty often find the Power Legging feels unexpectedly firm on first wear. This is normal — the fabric softens slightly after washing and adapts to your body shape over the first 3–5 wears.
6 | How to Measure Yourself
Three Key Measurements for Activewear
- Bust: Measure around the fullest part of your chest, keeping the tape horizontal. Wear a non-padded bra or no bra. Do not pull tight.
- Waist: Measure around your natural waist — the narrowest part of your torso, approximately 2–3cm above your navel.
- Hips: Measure around the fullest part of your hips and bottom — typically 18–23cm below the natural waist.
For leggings, hips is the most important measurement. For tops, bust is the primary reference. For sports bras, you need both band (underbust) and bust measurements as described in section 4.
If your measurements fall between two sizes in the table, the tiebreaker is the activity type: go down a size for compression and performance, go up for comfort and casual wear.
Shop Sweaty Betty at OD's
Every piece below is in stock at OD's Designer Clothing — authorised UK stockist.