Clothing Size Charts for Women: How to Read Them Right

A size chart looks like a measurement of you. It is not. It is one brand’s record of how it cut its own garments, published in inches so you can check whether your body falls inside them. Read it that way and most of the frustration goes somewhere useful: you stop asking what size you are, and start asking what this chart says about this garment.

That shift matters more the further you sit from the middle of a brand’s range, because that is where the scales stop lining up.

There is no standard behind the number

Start here, because it explains everything downstream. Wikipedia’s survey of clothing sizes states plainly that “There is no mandatory clothing size or labeling standard in the US.” A federal sizing guide did exist; it “was eventually degraded to a voluntary standard until it was abolished altogether in 1983.”

Nothing replaced it with any force. ASTM International publishes body measurement tables that manufacturers may use as a design baseline, and many do, but using them is a choice. The result is the one you would predict: “the dimensions of two size 10 dresses from different companies … may have grossly different dimensions.”

So when a chart says 14, that number is not a claim about a body. It is a label on a pattern.

Two tables, not one scale

Here is the part that decides everything below, and it is easy to read past. ASTM maintains two separate tables for adult women:

ASTM D5585 — Standard Tables of Body Measurements for Adult Female Misses Figure Type, size range 00–20
ASTM D6960/D6960M — Standard Tables for Body Measurements for Plus Women’s Figure Type, size range 14W–40W

Read those ranges again. They overlap from 14 to 20, and they are different tables describing different figure types. A 14W was never drafted as “a 14, but bigger.” It is a 14 from the other table, drawn for a different figure type — which is what the two titles say, and as much as we can tell you.

The standards themselves are paywalled, so we are quoting only the ranges in their titles — we cannot tell you what is inside them, and we are not going to pretend otherwise. You do not need the standards to see the effect, because retailers publish the consequence themselves.

What that looks like in one real chart

Lands’ End publishes a women’s trouser chart that lists Misses and W sizes in the same table, in both inches and centimetres. Four rows from it:

Size	Waist (in)	Hips (in)
L 16	35 – 36½	44½
XL 18	37 – 38½	46½
0X 14W	36½ – 37½	44½
1X 16W	38 – 39	46

Look at the 16 and the 14W. The 14W has the larger waist — 36½–37½ against 35–36½ — while both list the same 44½ hip. The 16W, at a 38–39 waist, sits above the 18. The W sizes are not their plain-number twins shifted up by a fixed amount, and they are not smaller either. They are a different ruler laid alongside the first one.

This is one retailer’s chart and it is theirs alone; another brand’s numbers will differ. That is rather the point. What it demonstrates is structural: the two scales are not convertible by arithmetic, so “I’m a 16, so I’m a 16W” is a guess dressed up as a conversion.

Letters are worse

If numbers travel badly between brands, letters barely travel at all. Universal Standard, which sells 00 through 40, publishes this mapping: L = 22–24. The Lands’ End chart above puts L = 14–16.

Same letter, six to ten numbers apart — 22 − 16 at the closest, 24 − 14 at the widest. Neither brand is wrong. They are labelling different parts of their own ranges, and an L means “toward the middle of what we make” — nothing more.

What the numbers were supposed to mean

Europe took a different route, and it is worth knowing about because it shows what a size label could be. EN 13402 defines which body dimension leads for each garment type — bust girth for dresses, knits and blouses; waist girth for trousers, shorts and skirts; underbust plus bust for bras — and it says a garment “should not be labelled with the average body dimension for which the garment was designed.” Instead, “the label should show the range of body dimensions from half the step size below to half the step size above the design size,” such as “height: 172–180 cm.”

A range, on the label, in body measurements. That is what you are reconstructing by hand every time you hold yourself up against a chart.

There is an arithmetic behind the traditional numbers too. The familiar formulas tie dress size to bust circumference in inches: US size = bust − 28, UK size = bust − 24. A 40-inch bust lands on a US 12 and a UK 16 — which, as it happens, is where the four-size gap between the two systems comes from.

Those formulas describe the historical logic of the scale. They do not describe what any particular brand cut this season.

How to actually use a size chart

Measure yourself, not a garment you own. Bust at the fullest point, waist where you actually wear your waistband, hips at the fullest point. Duluth Trading’s own instruction for the waist generalises well: measure “slightly below your natural waist, where you normally wear your pants,” and “insert your forefinger between the tape and your body to allow ease in fit.”
Write the numbers down once, in inches and centimetres. Your measurements change slowly. The charts change every season.
Use the chart on the page you are buying from. Not a generic conversion table, not the size you wore at another brand, not the size you wore last year at this one.
Let your largest measurement pick the size. A garment that is too small at the hip cannot be rescued; a waist that comes up slightly loose usually can.
Check which measurement the garment is cut around. Trousers and skirts are governed by the waist, dresses and tops normally by the bust. If you match two of three numbers, make sure you match the one that governs.
Expect the W boundary to need its own check. Anywhere near 14–20 you are standing where the two tables overlap, and the same brand may fit you differently in an 18 and an 18W.

Where this gets you

You cannot make brands agree, and no chart on the internet can do it for them. What you can do is stop reading the number on the label as information about your body, keep four measurements on your phone, and treat every chart as the single-brand document it is.

The rest of this section works the same way — measurements first, labels second. The other guides in size guides take the individual measurements one at a time: what to measure, where to hold the tape, and which number the garment is actually cut around.

Sources

Clothing sizes — Wikipedia — absence of a mandatory US standard, the 1983 abolition, the bust-based size formulas
ASTM D5585-21 and ASTM D6960/D6960M-16(2023) — the two tables and their size ranges (titles only; the standards themselves are paywalled)
Lands’ End women’s trousers size chart — the 16, 18, 14W and 16W rows quoted above
Universal Standard size finder — the letter-to-number mapping
EN 13402 — Wikipedia — primary dimensions per garment type and range labelling
Duluth Trading size guide — the waist measuring instruction

Frequently asked questions

Is there an official women's clothing size standard in the US?

No. There is no mandatory clothing size or labelling standard in the United States. A federal sizing guide existed, was downgraded to a voluntary standard, and was abolished altogether in 1983. ASTM publishes body measurement tables that brands may use as a design baseline, but nothing requires them to.

Why is a 14W not the same as a 14?

They come from different tables. ASTM D5585 covers the Misses figure type in sizes 00 to 20; ASTM D6960 covers the Plus figure type in 14W to 40W. They are separate scales that happen to share numbers, so a W size is not a larger version of the same number.

Should I trust the letter size or the number?

Neither on its own. Universal Standard maps L to sizes 22 to 24; the Lands' End women's chart maps L to 14 to 16. Letters are the least comparable label across brands. Compare your own bust, waist and hip measurements against the chart on the page you are buying from.