Which Measurement Decides Your Dress Size?

Most people’s bust, waist and hip measurements fall in two or even three different sizes on a chart. That is normal — size charts assume one proportion and bodies come in many. The practical question is which measurement decides your dress size, and the answer depends entirely on the shape of the dress.

This guide explains the rule, applies it to each common dress shape, and shows what to do with the measurements that do not decide the size. More in our Size Guides section.

Size by the measurement the dress fits most closely. For a fitted dress that is the largest of your three; for an A-line it is bust and waist; for a wrap or empire dress it is mainly the bust. Alter the rest.

Why Your Measurements Land in Different Sizes

A size chart links each size to one bust, one waist and one hip measurement, based on a single assumed proportion. Your own proportion is almost certainly slightly different — perhaps a smaller waist relative to the hip, or a larger bust relative to both. That is not a problem with your body; it is the limit of a chart built on one shape.

If you have not measured yet, read how to measure for a dress first.

The Rule

A dress only needs to fit closely where it is designed to fit closely. Everywhere else it has room — ease — built in. So the deciding measurement is the one where the dress is closest to the body, and where there is the least spare fabric to adjust.

When two measurements both matter, size by the larger of them. A dress can almost always be taken in; it can rarely be let out by much.

Dress Shape by Dress Shape

Dress style	Size by	Why
Fitted sheath or bodycon	Largest of the three	It has to fit everywhere
A-line or fit-and-flare	Bust and waist	The skirt has room at the hip
Wrap dress	Bust	The waist adjusts with the tie
Shift or relaxed	Bust and hip	No defined waist
Empire waist	Bust	Everything below falls loose
Shirt dress	Bust and shoulder	Buttons must lie flat

A Worked Example

Imagine measurements that fall in size 12 at the bust, size 10 at the waist and size 14 at the hip.

Fitted sheath: size 14, the largest, then take in the bust and waist.
A-line: size 12, by the bust and waist — the skirt has room for the hip.
Wrap dress: size 12, by the bust — the tie handles the waist.
Shift: size 14, by the hip, since a shift must clear it without pulling.

Bust in size 12, waist in size 10, hips in size 14. An A-line dress in size 12 fits, because its skirt has room through the hip — while a fitted sheath needs a 14, taken in at the bust and waist.

Enter all three measurements and choose a style; the calculator does this reasoning for you and tells you which measurement is deciding.

What to Do With the Other Measurements

The measurements that did not decide the size are where alterations come in. Taking in a bodice, a waist or side seams is routine and inexpensive. Include it in the price when deciding if a dress is worth it — the cost per wear calculator has a field for alterations.

If you are regularly two sizes apart in the same direction — a hip larger than the bust, say — look for shapes built around that proportion. A-line and fit-and-flare suit a hip larger than the bust; empire and shift suit a fuller middle. The body shape calculator identifies your proportion, and how to dress for your body shape goes further.

Check the fabric before deciding. Stretch jersey gives at the deciding measurement; structured woven fabric does not. A stretch dress can often be sized by the smaller measurement; a woven one should be sized by the larger.

Related Guides

Dress types and how they fit covers each shape in detail, and what to do between sizes applies the same rule to other garments. For a brand known for running small, see the Zara dress size guide; for bridal sizing, wedding dress shopping: what to expect. For tops and trousers, use the clothing size converter.

Frequently Asked Questions

Which measurement is most important for dress size?

It depends on the shape. Fitted dresses need the largest of the three; A-line depends on bust and waist; wrap and empire mainly on the bust.

What if my bust and hips are different sizes?

That is normal. Size by the measurement the dress fits most closely, and alter the rest.

Should I size by my bust or my hips?

By the bust for wrap, empire and A-line dresses; by the hips for shifts and fitted dresses where the hip is your largest measurement.

Why do size charts not match my body?

Charts assume one proportion for each size. Most bodies differ from it somewhere, which is why measurements land in different sizes.

Can a dress be let out?

Only a little, and only if there is spare fabric in the seams. Taking in is far easier, so size by the larger measurement.

For how European sizes are built on body measurements, see EN 13402, and for US conventions, US standard clothing size.

How to Measure Hat Size, and Convert It to Any System

Hat sizing is simpler than it looks, because it rests on a single measurement: the circumference of your head where the hat will sit. Everything else — US fractions, UK fractions, S-M-L — is just a different way of writing that number. Knowing how to measure hat size takes two minutes and a soft tape measure.

This guide shows where to measure, how to convert the number, and what to do if you land between sizes. More in our Size Guides section.

Measure around your head about one finger’s width above the ears and across the middle of the forehead. Your head circumference in centimetres is your European hat size.

What You Need

A soft, flexible tape measure
Or a piece of string and a ruler
A mirror, to check the tape is level
Your hair styled the way you usually wear it under a hat

How to Measure Your Head

Place the tape across the middle of your forehead, about a finger’s width above the eyebrows.
Take it around the sides of your head, about a finger’s width above the ears.
Bring it around the fullest part of the back of your head.
Keep it snug and level — touching all the way round but not pressing in.
Read the number where the tape meets, then measure again to confirm.

No tape measure? Wrap a piece of string around the same line, mark where it meets, then lay it flat against a ruler. The result is just as accurate if you keep the string level.

Converting Your Measurement

The European system is the simplest: your head circumference in centimetres is your hat size, so a 57 cm head wears a size 57. US hat sizes are based on the diameter in inches, and UK sizes run one-eighth smaller than US.

Head (cm)	Head (in)	European	US	UK	Letter
54	21¼	54	6¾	6⅝	XS
55	21⅝	55	6⅞	6¾	S
56	22	56	7	6⅞	S
57	22½	57	7⅛	7	M
58	22⅞	58	7¼	7⅛	M
59	23¼	59	7⅜	7¼	L
60	23⅝	60	7½	7⅜	L
61	24	61	7⅝	7½	XL
62	24⅜	62	7¾	7⅝	XL

Letter sizes vary between brands more than any other system. Use them as a rough guide, and check the brand’s own chart when a hat is sold in S, M and L.

The calculator converts your measurement into every system at once and gives the head-shape guidance that most charts leave out.

If You Are Between Sizes

Choose the larger size. A hat slightly too big can be made smaller with a sizing insert or hat tape inside the band; a hat too small is uncomfortable and leaves a red mark, and stretching it is harder. What to do between sizes covers the same rule for other garments.

Head Shape Matters Too

Heads are not perfectly round. Some are longer front to back; others are rounder. Two people with the same circumference can find the same hat fits one comfortably and presses at the front and back on the other. If a hat in your size presses at the forehead and the back but gaps at the sides, the shape is the issue, not the size — how a hat should fit explains what to look for.

For the styles themselves, see hat types and sizing and the best hats for your face shape, with the face shape detector if you do not know yours. To keep a good hat in shape, read how to store and care for a felt hat. The same measure-first approach works for gloves — try the glove size calculator.

Frequently Asked Questions

How do I measure my hat size?

Wrap a soft tape around your head about a finger’s width above the ears and across the middle of the forehead. The circumference is your size.

What is my European hat size?

Your head circumference in centimetres. A 57 cm head wears a European size 57.

What is the difference between US and UK hat sizes?

UK sizes run one-eighth smaller. A US 7⅛ is a UK 7.

Should I size up or down in hats?

Up. A slightly large hat can be adjusted with a sizing insert; a small one cannot easily be made bigger.

Can I measure my hat size without a tape measure?

Yes. Use a piece of string around the same line, mark where it meets, and measure the string against a ruler.

For background on how hat sizes are defined in different countries, see hat size, and for the traditional craft, hatmaking.

How to Measure for a Dress: Bust, Waist, Hips and Length

Dress sizes are built on three body measurements — bust, waist and hips — and ordering online without them is guesswork. Learning how to measure for a dress takes five minutes, a soft tape measure and a mirror, and it matters more for dresses than for almost anything else, because a dress has to fit in three places at once.

This guide covers how to take each measurement, the two extra ones that matter for some styles, and how to turn the numbers into a size. More in our Size Guides section.

Measure your bust at the fullest point, your waist at the narrowest, and your hips at the widest, with the tape level and snug but not tight. Then let the dress’s cut tell you which of the three matters most.

What You Need

A soft, flexible tape measure — not a metal one
A full-length mirror, to check the tape is level
The underwear you plan to wear with the dress
Somewhere to write the numbers down
Someone to help, if you can — it makes the bust and length easier

The Three Main Measurements

Bust

Measure around the fullest part of the bust, keeping the tape level across your back and under your arms. Keep your arms relaxed at your sides, and wear the bra you plan to wear with the dress — it changes the number.

Waist

Measure around your natural waist, which is the narrowest part of the torso, usually a little above the belly button. If you are not sure where it is, bend slightly to one side; the crease that forms is your natural waist. Stand relaxed and breathe normally.

Hips

Measure around the fullest part of your hips and seat, with your feet together. The fullest point is often lower than people expect, so check in the mirror that the tape is level.

Keep the tape snug but not tight — you should be able to slide one finger under it. A tape pulled tight gives a number that fits only while you hold your breath.

Two Extra Measurements for Some Styles

Length

For midi and maxi dresses, measure from the top of the shoulder, where a strap would sit, down to where you want the hem. Wear the shoes you plan to wear, since heels change the length you need.

Shoulder Width

For structured and tailored dresses, measure across the back from the edge of one shoulder to the other. It matters for anything with set-in sleeves, where the shoulder seam has to sit in the right place.

Which Measurement Decides Your Size

Most people’s three measurements do not all land in the same size. Which one to use depends on the cut of the dress — and this is where most dress sizing goes wrong.

Dress style	Size by	Why
Fitted sheath or bodycon	Largest of the three	It has to fit everywhere
A-line or fit-and-flare	Bust and waist	The skirt has room at the hip
Wrap dress	Bust	The waist adjusts with the tie
Shift or relaxed	Bust and hip	No defined waist
Empire waist	Bust	Everything below falls loose

The full explanation is in which measurement decides your dress size, and dress types and fit covers each shape in detail.

Choose the size that fits your largest relevant measurement, then have the rest taken in. A dress can almost always be taken in; it can rarely be let out by much.

Turning Measurements Into a Size

Enter all three measurements and choose a style. The calculator tells you which measurement is deciding your size, and gives it in European, UK and US numbers.

If your measurements fall between two sizes, read what to do between sizes. For a brand known for running small, see the Zara dress size guide; for bridal sizing, which works differently again, wedding dress shopping: what to expect. The clothing size converter covers tops and trousers, and the body shape calculator uses the same three measurements plus shoulders. For trousers, see how to measure for jeans.

Frequently Asked Questions

How do I measure myself for a dress?

Measure your bust at the fullest point, your natural waist at the narrowest point, and your hips at the widest point, with the tape level and snug but not tight.

Where is my natural waist?

The narrowest part of your torso, usually a little above the belly button. Bend slightly to one side — the crease that forms is your natural waist.

Should I measure over clothes?

Measure over thin underwear, ideally the bra you plan to wear with the dress. Clothes add bulk and change the numbers.

What if my measurements are different sizes?

That is normal. Size by the measurement the dress’s cut depends on most, and have the rest altered.

How do I measure dress length?

From the top of the shoulder down to where you want the hem, wearing the shoes you plan to wear.

For how European sizes are built on body measurements, see EN 13402, and for US conventions, US standard clothing size.

How to Measure for Jeans: Your Body, or a Pair That Fits

Jeans are the hardest thing to buy online, because denim sizing varies more between brands than almost any other garment and because five different measurements affect the fit. Learning how to measure for jeans takes ten minutes and a tape measure, and removes most of the guesswork from ordering.

There are two ways to do it: measure your body, or measure a pair of jeans that already fits you well. Both are covered below. When they disagree, the pair that fits is usually the better guide — it already reflects how you like denim to sit. More in our Size Guides section.

Measure a pair of jeans that already fits well, laid flat. It is usually more accurate than measuring your body, because it captures how you actually like jeans to fit.

What You Need

A soft, flexible tape measure
A flat surface such as a table or the floor
A pair of jeans that fits you well, if you have one
Someone to help with the inseam, if measuring your body
Somewhere to write the numbers down

How to Measure Your Body for Jeans

Waist

Measure where the jeans will actually sit, which is not always your natural waist. A high-rise jean sits near the natural waist; a mid-rise sits lower, around the top of the hip bones. Keep the tape level and snug, but not tight.

Hips

Measure around the fullest part of your hips and seat, standing with your feet together. Keep the tape parallel to the floor all the way round.

Inseam

Measure from the crotch down the inside of the leg to the point where you want the hem. Stand straight, and have someone else hold the tape if you can — bending to read it changes the number.

Rise

The distance from the crotch to where the waistband sits. It decides whether a jean feels high or low, and is easiest to take from a pair of jeans rather than your body.

Thigh

Around the fullest part of one thigh, just below the crotch. It matters most for slim and straight fits.

Measure over thin underwear, standing naturally. Breathing in or pulling the tape tight gives a number that fits for about a minute.

How to Measure a Pair of Jeans That Fits

The more accurate method. Lay the jeans flat, buttoned and zipped, and smooth out any wrinkles.

Waist

Straight across the top of the waistband from edge to edge, then double the number.

Hip

Straight across, about three inches below the bottom of the waistband, then double it.

Inseam

From the crotch seam down the inside leg seam to the hem.

Front Rise

From the crotch seam straight up to the top of the waistband at the front.

Leg Opening

Straight across the hem, then double it. Useful when comparing straight, wide and slim fits.

Stretch denim measured flat will read smaller than it wears. Compare it with the stretch content of the jeans you are buying — a rigid pair and a stretch pair with the same flat measurement will not fit the same.

When the Two Methods Disagree

Body measurements tell you what you are; garment measurements tell you what you like. Most people wear jeans slightly looser or tighter than their body measurement suggests, and the pair you reach for every week already encodes that preference.

Where the two disagree, trust the garment — unless the pair you measured is one you have never been quite happy with. In that case, use your body measurements and read how jeans should fit to decide how much ease you want.

Your jeans waist size is the same as your natural waist measurement. Jeans sit wherever their rise puts them, which is often below the natural waist, and stretch fabrics are cut smaller than the body measurement. Measure where the jeans will actually sit.

Turning Measurements Into a Size

Enter your waist and hips, and your inseam if you have it. The converter gives your size across systems and shows how brands compare.

For an example of how one brand labels waist and length, see the Levi’s size chart explained. If you are tall, read jeans for tall women; for which cut suits your proportions, jeans for your body shape and the body shape calculator. The same measuring habits apply to dresses — see how to measure for a dress and the dress size calculator. Between sizes? What to do between sizes covers it.

Frequently Asked Questions

How do I measure myself for jeans?

Measure your waist where the jeans will sit, your hips at the fullest part, your inseam from crotch to hem, and your rise. Keep the tape snug but not tight.

Where should I measure my waist for jeans?

Where the jeans will sit, which depends on the rise — near the natural waist for high rise, lower for mid rise.

How do I measure my inseam?

Stand straight and measure from the crotch to where you want the hem. It is easier and more accurate with someone else holding the tape.

Is it better to measure myself or my jeans?

A pair of jeans that already fits well is usually the more accurate guide, laid flat and measured.

What is the rise on jeans?

The distance from the crotch seam to the top of the waistband. It decides whether the jeans sit high or low on your body.

For background on how clothing sizes are standardised, see EN 13402, the European size-labelling standard, and on the measurement itself, inseam.