Sweaty Betty Sizing, Measured: The 10 on Its Chart Is a US 6

Read this first — Ignore the digits and use the waist inch. A US 10 shopper is not a Sweaty Betty 10; by the brand's own conversion table she is a UK 14, which the chart calls L and gives a 31" waist and a 42" hip.

Most of the sizing confusion around this label has nothing to do with how tight the fabric is. It comes from arithmetic. Sweaty Betty is a British brand, the size chart on its US storefront is still built on UK dress sizes, and the numbers in that top row happen to look exactly like American ones.

What size is a Sweaty Betty 10 in US sizes?

A US 6. That answer comes from the brand's own international conversion table, printed further down the same page as the leggings chart.

Source: Sweaty Betty size guide, International Conversions table, checked Sept. 21, 2026.

Two sizes of slippage runs all the way up the ladder. Australian sizes match the UK column exactly, which is why an Australian reader can take the digits at face value and an American cannot. The EU column is the UK number plus 28.

What does the leggings chart measure, in inches?

Body measurements, not garment measurements — the page tells you to measure yourself in your underwear, take the waist slightly below the natural waist where you normally wear your trousers, and take the hip at the fullest part. Here is the leggings chart as published, with the centimetre figures the brand prints alongside each inch.

Source: Sweaty Betty size guide, Leggings Size Chart, checked Sept. 21, 2026.

Every one of those cm-to-inch pairs converts correctly, which is worth saying because plenty of charts do not. The waist grades in exact 2" steps from XXS through XL, and the hip does the same. Only the last rung breaks the pattern: XXL adds 3" at the waist and 2.5" at the hip. If you sit between XL and XXL, that is a wider gap than anywhere else on the chart, and it is the one place where the between-sizes decision costs you the most.

One number is missing that many shoppers want: there is no garment measurement anywhere, so nothing tells you how much the waistband stretches or how far it recovers. That is a gap this brand shares with almost everyone; we go through what garment figures would change in the piece on brands running more than one chart.

Is Sweaty Betty's ladder narrower than other brands'?

At the small end it lines up neatly with Girlfriend Collective and sits a full rung below Beyond Yoga. Same letters, three charts, waist in inches:

Sources: Sweaty Betty size guide; Girlfriend Collective sizing, Bottoms chart; Beyond Yoga size guide. All checked Sept. 21, 2026.

Read across the S row and the problem shows itself. Sweaty Betty's S is 27", which falls inside Girlfriend's 26–28" band, while Beyond Yoga's S starts at 28" — an inch above where Sweaty Betty's S stops being right for you. A 28" waist is a Sweaty Betty M, a Girlfriend S or M depending on which way you round, and a Beyond Yoga S. Three brands, one body, three different letters.

The hips tell a second story. Sweaty Betty publishes a single hip value where Girlfriend publishes a band, and that single value starts at the top of Girlfriend's band and drifts to the bottom of it as the sizes go up: 34" against Girlfriend's 32–34" at XXS, but 44" against Girlfriend's 44–46.5" at XL. Girlfriend grades 18" of hip across its first seven sizes; Sweaty Betty grades 12.5". If your hip-to-waist difference is large, that matters more than the waist number does, and we pulled those drops apart in the waist-to-hip note.

Beyond Yoga publishes no hip measurement on that chart at all, only bust and waist, and its extended run leaves a hole: XXL tops out at 39.5" while 1X starts at 41". Nothing on the page covers a 40" waist. Sweaty Betty's leggings chart simply stops at XXL / 36" / UK 18–20, with no extended sizes below it — the shortest of the three ranges by a wide margin, since Girlfriend runs to 6XL at a 49.5–53" waist.

How long is each Sweaty Betty legging length?

The brand names four lengths and gives an inseam for each, which puts it ahead of most of its competition. The descriptions in brackets are the brand's own.

Source: Sweaty Betty size guide, Inseam Leggings table, checked Sept. 21, 2026.

Trousers carry their own numbers. Yoga trousers run capri 61 cm / 24", short 67 cm / 26" and regular 81 cm / 32". The Gary Taper comes in short at 63.5 cm / 25" and regular at 68.5 cm / 27". The Gary Luxe runs a touch longer, short at 66 cm / 26" and regular at 71 cm / 28". A 27" inseam turning up as both a legging full length and a Gary Taper regular is the kind of overlap that makes ordering across categories easier than it usually is.

That 27" full length is a genuinely short full length. For context on where each number lands on a leg, see inseam by height; if 27" sounds too short for you, the 31" tall note covers who needs the longer end. The 24" 7/8 is standard for the category, and the capri and 7/8 chart puts it beside other brands.

Is there a mistake in the published crop length?

There appears to be. Capri is listed at 43 cm and 17", which converts correctly — 43 cm is 16.9". Crop is listed at 50 cm and, again, 17". But 50 cm is 19.7", nearly three inches longer than the figure printed beside it.

So the two rows cannot both be right. Either the crop inseam is 50 cm and the inch column should read about 19.7", or the crop really is 17" and the centimetre figure is overstated. Given that capri and crop are described as different lengths — one mid-calf, one "just below the knee" — the centimetre figures are the ones that behave like two distinct garments, and the inch column looks like the copy-paste.

We are flagging it rather than resolving it, because we have not measured a pair. If you are buying crop specifically, treat 19.7" as the working assumption and check the product page for that style. Charts disagreeing with themselves is common enough that we keep a running file of it in Brand Notes.

What does the brand tell you to do between sizes?

Size up. The guide says it plainly: if your measurements fall between two listed sizes, pick the next size up. That is the opposite of what compression-heavy labels usually advise, and with 2" gaps on this ladder it means a 28" waist goes to M rather than S.

There is a second instruction that is easy to miss, and it is about height rather than width: if you are 5'4" or under, the brand recommends wearing the 7/8 as your full length. At 24" against the 27" full length, that is a 3" difference. Returns run 45 days, unworn, unwashed and unaltered, which gives you room to test one size against another.

Which numbers should you carry to the checkout?

Three: your waist in inches, your hip in inches, and the inseam of a pair you already like. The letter follows from those, and how to take them matters more than which brand you are buying from.

Then do the translation once. Find your waist on the chart above, note the letter, and only afterwards look at the UK digit so it does not anchor you. Somebody at 29" waist and 40" hip is an M here, a UK 12, a US 8 — and if she shopped Beyond Yoga on the same day she would still be an M, but at Girlfriend she would be an M by waist and an M by hip only just. Cross-brand letters are not portable, which is the whole reason we chart them side by side in the five-brand label comparison.

For brands whose charts we have already taken apart, CRZ Yoga prints its inseam in every product title, and Baleaf runs five different chart versions under one name. The CRZ against Girlfriend comparison uses the same Girlfriend numbers quoted above, so the two pages should agree to the inch.

Sources

• Sweaty Betty — Size Guide (Leggings Size Chart, Trousers Size Guide, International Conversions, How to measure, Between sizes, Returns), checked Sept. 21, 2026.
• Girlfriend Collective — Sizing Guide (Bottoms chart), checked Sept. 21, 2026.
• Beyond Yoga — Size Guide (US size chart), checked Sept. 21, 2026.

Charts change without notice. Every figure above was read off the brand's own page on the date given; if a number here no longer matches the source, the source wins.