Why one brand's medium is another brand's small

Nobody regulates clothing sizes. There is no standards body that says a women’s medium has to be a 36-inch bust, and no penalty for a brand that decides it means 38. Every label works from its own block – the master pattern its garments are cut from – and blocks drift apart over decades of a brand serving slightly different customers.

That is the whole explanation for why you own a small from one label and a large from another, and why neither is wrong.

What actually varies

Three things, mostly:

• The base measurement. One brand’s M is a 37-inch chest, another’s is 39. A two-inch gap is a full size.
• Ease. The deliberate extra room added on top of the body measurement. A tailored shirt might add two inches; a relaxed one adds six. Same body, same nominal size, very different garment.
• Grading. How much a brand adds when it steps from S to M to L. Some grade evenly across chest, waist and hem; others add most of it at the waist. If your shoulders and your waist disagree about your size, grading is usually why.

Measure the garment, not yourself

Body measurements sound authoritative but they are the wrong tool for online shopping, because they tell you nothing about ease. A 38-inch chest fits into garments labelled anywhere from 38 to 46 inches depending on how the brand intended it to sit.

The reliable method takes two minutes:

1. Find a garment you already own in roughly the same category – a shirt for a shirt, a coat for a coat. Pick one that fits the way you want the new one to fit.
2. Lay it flat on a table. Do not stretch it.
3. Measure straight across from armpit seam to armpit seam. Double that number – that is the chest measurement.
4. Measure the length from the highest point of the shoulder straight down to the hem.
5. Compare those two numbers to the chart.

Two numbers beat a full body survey, because they carry the ease decision already baked in. If your favourite jumper measures 44 inches around and feels right, buy the 44-inch one – whatever letter is on the label.

The rules of thumb that hold up

• Knitwear and outerwear: size up. They are designed to go over something.
• Stretch denim: size down. Anything with elastane relaxes by roughly half a size within a few hours of wear, and it does not come back until you wash it.
• Rigid denim: size up, or at least do not size down. It has nowhere to give.
• Jersey tees and dresses: true to size. Jersey is forgiving in both directions.
• Tailored shirting: the neck and the sleeve decide it, not the chest.

What we do about it

Because BGalz resells rather than manufactures, we cannot force every brand in the catalogue onto one block. What we can do is name the manufacturer and the model number on every product page, so you can look up that brand’s own chart if you want a second opinion. Our Size Guide is the general chart; the brand’s own chart, where the two disagree, is the one to trust.

And if it still arrives wrong, a size return is a change-of-mind return: you pay the postage, we charge no restocking fee, and the item price plus the duty you paid on it comes back. That is written out in full on the returns page.