Clothing size labels differ because there is no single size chart that every brand has to follow. Each maker designs around its own idea of its customer, its own fit and its own style, and sizing has also changed over the decades. So a size 12 or a medium is a rough starting point, not a promise. The reliable way to find your fit is to measure yourself once, measure a garment that fits you well, and compare those numbers in cm with the garment you want to buy.
That matters most when you are buying second-hand, where one rail can hold clothes from many brands and many years. Here is why labels vary and how to get round it.
Why the same size fits differently
No single standard
UK sizes such as 8, 10 and 12 for women, or chest and waist sizes for men, are common conventions, not fixed measurements. A brand decides what its size 12 measures, and another brand may decide differently.
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Different fits for different customers
Makers design for the shape and style they have in mind. One might cut its trousers straighter through the hip, another more generously through the thigh. One might cut a shirt slim, another relaxed. The size on the label is the same, but the garment is not.
Style and intent
An oversized jumper is meant to be big. A slim-fit shirt is meant to be close. The same person might wear a small in one and a large in another, and both could be the right fit.
Changes over time
Sizing has changed over the decades, and older and vintage pieces often come up smaller than the label suggests to a modern shopper. Our guide to buying vintage clothing covers that in more detail.
Fabric and washing
Stretch fabrics fit more closely than rigid ones in the same size. Natural fibres such as cotton and wool may have shrunk a little in the wash, which second-hand clothes have often been through.
Step 1: measure yourself
You only need to do this once, then update it now and then.
- Bust or chest: round the fullest part, arms relaxed.
- Waist: round your natural waist, usually the narrowest point.
- Hips: round the widest part.
- Inside leg: from the crotch to the ankle.
Keep the tape level and snug, not tight. Write the numbers down in cm. On Rewear, you can save your measurements in your profile, and we use them to tell you how a piece will fit when it has been measured.
Step 2: measure something that fits
This is the most useful trick of all. Choose a piece you love the fit of, such as your favourite jeans, a jumper or a coat, lay it flat and measure it.
- Chest: armpit to armpit, then double it.
- Waist: across the waistband, then double it.
- Length: from the highest point of the shoulder to the hem.
- Inside leg: from the crotch seam to the hem.
These numbers include the room you like, so they are the best guide to what will feel right. Our guide to measuring clothes shows which measurements matter for each kind of garment.
Step 3: compare before you buy
Compare the garment's measurements with the ones you took. If they are within a centimetre or two of a piece that fits you, it is likely to fit too.
- Tops and jackets: chest and length matter most, and shoulders for structured pieces.
- Trousers and jeans: waist, hip, rise and inside leg.
- Dresses: bust, waist, hip and length.
- Coats: chest with room for a jumper, shoulders and sleeves.
If a listing has no measurements, ask. On Rewear, tap Message the seller. Measurements are optional, so not every piece has them, but many sellers are happy to measure.
Step 4: think about stretch and style
- Rigid fabrics, such as non-stretch denim, need to match closely.
- Stretch fabrics can be a little smaller and still fit.
- Oversized styles are meant to measure bigger than you, so compare them with something you wear loose.
When a conversion chart helps
If you are looking at a label from another country, a conversion chart gives a starting point. Our UK clothes size conversion guide covers EU and US sizes. Treat it as a first guess and confirm with the measurements.
Try the Will it fit? tool
If you have a garment's measurements, from a listing or anywhere else, our Will it fit? tool compares them with yours and tells you how it is likely to fit.
Selling? Measure for your buyers
If you sell, measurements in cm are the most useful thing you can add to a listing, because they answer the fit question before anyone has to ask. Lay the piece flat, measure the key points, and add them when you list. Our guide to measuring clothes for buying online shows exactly how.
The short version
Size labels vary because every maker sizes differently, and sizing has changed over time. Measure yourself once, measure a garment that fits, and compare those numbers in cm with anything you want to buy. Ask the seller when the measurements are missing.
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Find your next piece
Second-hand clothing from sellers across the UK, with measurements in cm where sellers add them and buyer protection at checkout.