A complete lingerie sizing guide

Sizing a bra is a skill most people develop through trial and error. Sizing a chemise, a bodysuit, or a silk sleepwear set is something else entirely — a different set of measurements, a different logic, and a different tolerance for error. Get a bra band wrong by one size and the fit is inconvenient. Get a silk chemise wrong and the return process is slow, the product has been handled, and the moment the piece was intended for has passed.

This guide covers sizing across the main lingerie garment types: bras, briefs, slips and chemises, bodysuits, sleepwear, and hosiery. It also addresses the particular challenge of ordering from boutique European vendors, where sizing conventions differ from UK and US standards in ways that are systematic and therefore learnable.

The goal is not to eliminate uncertainty entirely — fabric behaves differently across constructions, and every vendor's sizing is its own dialect — but to give you the reference points to make a confident estimate before you order, and to know what to do when the result is not quite right.

How lingerie sizing differs from clothing sizing

Clothing sizing in the UK and US is loosely standardised around a cluster of measurements — typically bust, waist, and hip — mapped to a label number or letter. Lingerie sizing uses a different set of references depending on the garment type, and boutique vendors are less likely than high-street retailers to map to a standard at all.

A bodysuit, for instance, may be sized by bust alone, by overall clothing size, or by a torso-length measurement. A chemise cut on the bias may be sized by hip rather than bust. Hosiery is typically sized by height and weight rather than by waist or hip measurement. None of this is irrational — it reflects what each garment actually fits around — but it means you cannot carry assumptions from one category to the next.

The first step, always, is to locate and read the vendor's size chart. Not the general guidance on the category page — the specific chart for the specific garment you are buying. Boutique vendors frequently size independently of one another, and CougarMetropolis publishes the vendor's own chart rather than mapping everything to a single house standard.

Measuring yourself correctly

Bust: measure across the fullest point of the bust, with the tape level and firm but not compressed. This is your over-bust measurement.

Underbust: measure directly below the bust, on the ribcage. This gives you the underbust reading used for bra band sizing and some bodysuit sizing.

Waist: measure at the natural waist — the narrowest point of the torso, typically an inch or two above the navel.

Hip: measure at the fullest point of the hips and seat, typically seven to nine inches below the natural waist.

Torso length: for bodysuits and long-line styles, measure from the top of the shoulder, over the bust, down to the crotch. This measurement prevents the common bodysuit problem of insufficient length causing pull and discomfort at the gusset.

Write these numbers down. They will be your reference for every order.

Sizing slips and chemises

A slip or chemise is typically sized by the larger of bust or hip, depending on the construction. A bias-cut chemise — one cut diagonally across the grain of the fabric — is sized by hip, because the fabric stretches across the bust but not the hips. A straight-cut or empire-waist chemise is sized by bust.

If your bust and hip measurements fall in different size brackets on a vendor's chart, size to the larger measurement. Fabric can accommodate a smaller measurement; it cannot accommodate a larger one.

See the guide to chemise sizing for a curvy figure for detailed guidance on reconciling bust and hip proportions in bias-cut styles.

Sizing bodysuits

A bodysuit adds the complication of torso length. Most sizing issues with bodysuits are not about circumference — they are about the fit pulling at the gusset or buckling at the waist because the torso measurement was not accounted for.

The practical approach: measure your torso length and compare it to the vendor's stated torso length for each size. If you are between sizes on circumference, the torso measurement should be the tiebreaker. A bodysuit that is too short in the body is unwearable; one that is slightly larger in circumference can often be managed with adjustment.

For waist-to-hip ratios outside the standard, see bodysuit sizing for an hourglass figure.

Sizing sleepwear

Silk and modal sleepwear is typically sized by bust or overall clothing size, with a generous ease allowance. The question is usually not whether the garment will fit — it is whether it will fit in the way you intend.

A pyjama set sized for comfort-wear will be cut with substantial ease. If you prefer a closer fit, size down. If you are between sizes and the fabric is woven rather than jersey, size up — woven fabric does not stretch and the consequences of too small are more limiting than those of too generous.

Modal and cotton-jersey sleepwear has more tolerance than silk, because the fabric recovers from stretch. Still, size charts should be checked against the inseam measurement for trousers and the torso length for tops, not only circumference.

The guide to choosing sleepwear size when you fall between sizes covers this in more detail.

Reading a European lingerie size chart

French, Italian, and German sizing for both bras and garments follow conventions that differ from UK and US sizing in a consistent way. For bras:

UK band sizes 32–40 correspond to French/Belgian sizes 85–100 (add 15 to the UK band number, then convert: 32 UK = 85 FR, 34 UK = 90 FR, and so on in increments of 5).
Cup letters are the same in UK and FR sizing up to DD, after which European sizing typically uses E, F, G while UK sizing uses DD, E, F.
Italian sizing for bras uses the same convention as French.
German sizing corresponds to FR sizing for bras.

For garments, European sizing is based on the bust measurement in centimetres, mapped to a label number: a 36-inch (91 cm) bust is approximately a European 40, a 38-inch (96 cm) bust is approximately a European 42. The step between sizes is typically 4 cm.

For a complete reference table, see how to read a European lingerie size chart.

Ordering online: reducing the risk of a poor fit

The single most important thing you can do before placing an order is read the size chart for the specific item, not the general sizing guide. Beyond that, look for:

Ease descriptions: does the vendor note whether the piece is cut slim, standard, or generous? This tells you whether to follow the chart or size up.
Fabric composition: a woven silk has no stretch. A stretch lace has significant give. The composition affects fit tolerance.
Returns information: a vendor with a clear return and exchange policy changes the risk calculation on an order where you are uncertain between two sizes.

For a fuller checklist, the guide to buying lingerie online covers what to read on a product page before you commit.

Sizing for a capsule wardrobe

If you are building a considered lingerie wardrobe rather than replacing single pieces, sizing becomes a coordinated exercise. The goal is a set of pieces that all fit correctly and cover the main occasions: everyday, occasion, and sleep. The capsule lingerie wardrobe guide offers a seven-piece framework with guidance on proportioning your investment across categories.

In this series

Browse the full lingerie edit on CougarMetropolis.