Is this a body chart or a garment chart?
There are two completely different tables that both get called a size chart, and retailers almost never label which one they have published. Reading one as though it were the other is the single most common sizing mistake, and it usually costs a whole size.
A body chart tells you what size body the garment was designed for. If it says a size 12 is 96 centimetres at the bust, it means the garment was cut to fit a person who measures 96 centimetres at the bust. Your own tape measurement goes straight into it.
A garment chart tells you how big the finished piece is when it is lying flat on a table. That number is always bigger than the body it fits, because a garment you can actually move in has to be larger than the person inside it.
The labels give it away once you know to look. Words that describe a person mean a body chart: bust, waist, hip, inside leg, neck. Words that describe an object mean a garment chart: chest width, pit to pit, across shoulder, total length, sweep, hem width.
If you compare your own bust measurement against a garment chart, every size will look far too big and you will size down into something that will not close.
What is ease on a size chart?
The gap between the body a garment was cut for and the garment itself is called ease. It exists so you can lift your arms, sit down and breathe.
How much ease a piece has is a design decision, and it varies enormously. A close tailored shirt might carry only a few centimetres at the chest. A relaxed overshirt might carry fifteen. A deliberately oversized jumper might carry twenty-five or more, and that is the whole point of it.
This matters when you are trying to judge a garment chart against yourself. A jacket with a 110 centimetre flat chest measurement is not a jacket for someone with a 110 centimetre chest. It is a jacket for someone smaller, and how much smaller depends on what the designer intended.
The way through this is to compare against a garment you already own rather than against your body. Take something in your wardrobe that fits the way you want the new piece to fit, lay it flat, measure across the chest, and compare that number to the one in the listing. You have now compared two garments, which is a fair comparison, and the ease question disappears.
Which measurement should you pick your size from?
People often try to satisfy every number in a size chart at once, find that their measurements land across three different rows, and conclude that they have measured wrong.
Almost nobody matches a chart exactly. A size chart describes one idealised body shape, scaled up and down in even steps, and real bodies vary in ways that no scaling covers. Landing on three different sizes is the normal result.
The way out is to work out which single measurement governs the garment in front of you. That is the widest point the piece has to pass over or sit on, and it is the one that decides whether the garment goes on at all.
- Jackets, coats, shirts, jumpers. The chest or bust governs. Almost everything with a sleeve is decided here, because a garment that is tight across the chest restricts the arms as well.
- Trousers, jeans, skirts. The hip governs, even though the waist is the number people reach for. A waistband can be taken in, belted or adjusted. The hip is where the garment has to physically pass over.
- Dresses. Whichever of bust, waist or hip is narrowest on the garment. Look at the photo: a dress fitted at the waist is governed by the waist, and one that falls straight from the bust is governed by the bust.
- Anything oversized or unstructured. Frequently nothing governs, which is why these charts often list only one measurement. Buy the size the shoulder works at and ignore the rest.
Once you have identified the governing measurement, match that row and stop. Use the other numbers only as a check that you have not misread the table entirely.
What do you do when you are between two sizes?
This happens constantly, because sizes commonly step in intervals of around four centimetres and bodies do not arrive in those steps.
The fabric answers it. In something rigid with no stretch, such as a woven cotton shirt, a structured jacket or heavy denim, size up. A garment that will not fasten is unwearable, and one that is a little loose is fine and often better.
In a knit, a jersey, or anything with elastane in the composition, size down. Those fabrics are designed to be worn under some tension, and the larger size will lose the shape the garment depended on.
There is a third case worth naming. If the garment is fitted at one point and loose everywhere else, such as a dress that is close at the waist and full through the skirt, size to the fitted point and let the rest of it be roomy. That is a garment you can wear. The reverse, a garment that fits everywhere except the one place it is tight, is one you will not.
How much bigger is the next size up?
Knowing roughly how much one size buys you turns a lot of guesswork into arithmetic. The step is commonly around four centimetres at the chest, waist and hip, and it often widens at the top of a range.
So if your measurement sits two centimetres above a row, going up a size overshoots by two centimetres. Sometimes that is fine. On a fitted garment it is the difference between well cut and wrong, and the honest answer is that a different cut will serve you better than a different number in the same cut.
This is also why a garment described as running small by one size is worth taking literally. It usually means the whole chart is shifted by roughly one step, and ordering one size up genuinely fixes it.
When should you not trust the chart on the page?
Two situations where the table on the page should be treated with suspicion.
The first is a chart that lists one measurement for a garment that is clearly fitted in several places. A single bust figure for a tailored dress is not enough information, and the absence is the retailer's shortcut rather than a sign the other measurements do not matter. Look in the product description for flat measurements, which are often buried there even when the chart is thin.
The second is a generic chart on a marketplace listing. That table frequently belongs to the platform rather than to the person who made the garment, so it describes an average rather than the item in front of you. Where a seller has measured the actual piece, use their numbers and ignore the chart entirely.
What does reading a chart look like in practice?
Say you measure 94 centimetres at the bust, 76 at the waist and 102 at the hip, and you are looking at a straight-cut wool coat.
Check the chart type first. It lists bust, waist and hip, so it is a body chart and your numbers go in directly. Now find the governing measurement: it is a coat, so the chest governs, and the hip figure matters only because the coat has to hang over it.
The chart puts 94 at the bust in size 12, and puts your 102 hip in size 14. Those disagree, which is the normal situation rather than a problem. The coat is straight cut and worn open, so the hip is not a point the garment has to close over. Take the 12.
Now change one thing: the coat is double breasted and belted at the waist. The waist has become a governing point, your 76 sits in size 12 on that chart too, and the answer stays the same for a different reason. Change it again and make the coat fitted through the hip, and the 14 becomes correct, with the shoulders wide.
The chart did not change in any of those three cases. What changed was which number was allowed to decide.
Which garments can a size chart not settle?
A few garments are genuinely poorly described by a size table, and knowing which ones saves you from over-thinking a number that was never going to settle it.
Heavily stretchy knits behave over a range rather than at a point, so two adjacent sizes may both work and feel different. Bias-cut dresses, where the fabric is cut diagonally across the weave, stretch and settle on the body in a way a flat measurement cannot capture. Anything with a drawstring, a tie waist or a wrap front adjusts across several sizes on purpose.
For all of those, the reviews are worth more than the chart, and the fit chapter on reading them covers how to get something reliable out of a review section.