May 4, 2026
Choosing sleepwear size when you fall between sizes
Fabric give, sizing up versus down for modal versus silk, and how vendor size charts differ from high-street ones.
Falling between sizes in sleepwear is a common experience, and the correct response depends on the fabric of the specific garment. The key variable is how much give the fabric has, which determines whether a slightly larger or slightly smaller size will result in a wearable fit.
Woven silk and charmeuse: size up
Woven silk has no stretch. A woven silk pyjama set or chemise that is one size too small will be tight across the bust, restrictive across the shoulders, and visually strained at every point that exceeds the garment's dimensions. A woven silk garment that is one size too large will have excess ease, which for sleepwear reads as a relaxed, comfortable fit rather than a poor one.
When between sizes in woven silk sleepwear: size up.
Modal and jersey: size up or down depending on the fit profile
Modal jersey and other knit fabrics have genuine stretch and recovery. The choice between sizing up or down depends on the fit profile of the specific style:
For close-fitting or body-hugging styles: size down or stay true to the smaller size. The jersey will stretch to accommodate; sizing up creates unnecessary excess.
For relaxed or pyjama-style cuts: size up. The relaxed silhouette benefits from a bit of additional ease, and the jersey will not create visual problems at a slightly larger size.
Checking the vendor's size chart
Boutique vendor size charts for sleepwear typically include bust, waist, and hip measurements for each size. The important additional information:
- Ease allowance: some vendors note whether the garment is cut slim, regular, or generous. A generous cut should be sized to the smaller measurement; a slim cut to the larger.
- Length: measure from shoulder to your intended hem position and compare against the specified garment length. Length is particularly critical for pyjama trousers and long nightgowns.
- Vendor-specific sizing: boutique sizing does not correspond to UK high-street sizing in any consistent way. A size M at one vendor may correspond to a 12 at a high-street retailer and a 14 at another boutique. The circumference measurements in the size chart are the reliable reference, not the size label.
The return policy consideration
When ordering between sizes, the return or exchange policy should be checked before purchase. A vendor who offers easy exchange makes the between-sizes decision much lower-risk — you can order both sizes and return the one that fits less well. A final-sale or difficult-returns policy changes the calculation.
The lingerie sizing guide covers sizing methodology for all garment types. For European sizing conventions specific to boutique vendors, see how to read a European lingerie size chart.