Quick answer: To find your UK dress size, measure your bust, natural waist and hips in centimetres, then compare each with the retailer’s size chart. If they fall in different sizes, choose the largest for a fitted dress and have it taken in. ASOS, for example, lists a size 12 as a 93 cm bust, 75 cm waist and 98.5 cm hip.
Dress sizes are not fixed measurements. A size 12 in one shop can be a 10 or a 14 in another, which is why measuring yourself is more reliable than going by the label in your wardrobe. This guide takes you through the three measurements that matter, shows how to read them against a chart, and explains which one to prioritise for different styles. It sits within our body and clothing measurement guides.
What do you need to measure your dress size?
- A soft tape measure with a centimetre scale. Most UK size charts now lead with centimetres. Our guide on reading a tape measure covers the markings.
- A well-fitting, non-padded bra, or the bra you would wear with the dress. Padding changes the bust figure.
- A mirror to check the tape is level at the back, or a friend to help.
- Somewhere to write the three numbers down, in centimetres and inches.
How do you measure for a UK dress size?
- Measure your bust. Stand straight with your arms relaxed. Wrap the tape round the fullest part of your bust, keeping it straight across your back, and read it without pulling tight. Our bust measuring guide has more detail.
- Measure your natural waist. This is the narrowest part of your torso, usually a little above the belly button and below the ribs. Bend sideways and it is where your body creases. Keep the tape snug and breathe out normally. See how to measure your waist for tips.
- Measure your hips. Put your feet together and wrap the tape round the fullest part of your bottom. Slide it up and down to find the largest reading. Our hip measuring guide explains how to find the widest point.
- Note your height. It does not change your size number, but it tells you whether petite, regular or tall ranges will fit best in length.
- Repeat each measurement once. If two readings differ, take the larger one.
How do you turn your measurements into a dress size?
Find each measurement on the retailer’s chart, note the size for each, then choose based on the style of dress. Charts list body measurements, not garment measurements, so you can compare your figures directly.
When a measurement falls between two sizes, read it as the larger size. A garment made for a 93 cm bust will be tight on a 95 cm bust, whereas a little extra room is easy to deal with. The calculator below uses the ASOS women’s dress chart to show where each of your measurements lands.
Dress size finder (ASOS chart, UK 4–18)
cm bust cm waist cm hips=The finder is a guide to one retailer's chart. Other shops use different numbers, so always check the chart on the site you are buying from.
What if your bust, waist and hips are different sizes?
That is normal, and the style of the dress decides which measurement matters most. Very few people match one size exactly on all three lines of a chart.
- Bodycon and sheath dresses fit closely everywhere, so go with the largest of your three sizes and have the rest taken in.
- Fit-and-flare and A-line dresses are fitted to the waist with a full skirt, so the bust and waist matter and the hips usually do not.
- Shift dresses hang straight from the shoulders, so the bust and hips decide the size.
- Wrap dresses adjust at the waist with a tie, so size by bust and hips.
- Empire-line and many maxi dresses are fitted only under the bust, so the bust measurement leads.
Worked example: one set of measurements, two retailers
The same body can be a size 12 at one shop and a size 14 at another. Take a bust of 92 cm, a waist of 74 cm and hips of 101 cm, and compare them with two published UK charts.
| Measurement | Your figure | ASOS size (chart value) | Hobbs size (chart value) |
|---|---|---|---|
| Bust | 92 cm (36.2 in) | 12 (93 cm) | 12 (95 cm) |
| Waist | 74 cm (29.1 in) | 12 (75 cm) | 12 (77 cm) |
| Hips | 101 cm (39.8 in) | 14 (103.5 cm) | 12 (102 cm) |
| Fitted dress | – | 14 | 12 |
| Fit-and-flare dress | – | 12 | 12 |
At ASOS the hips push a fitted dress up to a 14, while a fit-and-flare style stays at 12. Hobbs's chart is more generous at the hip, so a 12 works for both. Chart values are taken from each retailer's published size guide.
Does height change your dress size?
Height does not change the size number, but it decides whether petite, regular or tall ranges suit you. Petite and tall ranges keep the same bust, waist and hip measurements while adjusting lengths, such as the distance from shoulder to waist and the hem.
Each retailer sets its own height bands. Hobbs, for instance, describes its petite collection as designed for women 5 ft 3 in (160 cm) and under. If a dress lists its length, compare it with a dress you own: measure from the highest point of the shoulder seam straight down to the hem.
How do you check a size against a dress you already own?
Lay the dress flat, measure straight across at the bust, waist and hips, and double each figure. That gives the garment's actual circumference, which you can compare with any garment measurements listed on a product page.
- Do up any zips and buttons and smooth the dress flat on a table without stretching it.
- Measure the bust straight across from one underarm seam to the other.
- Measure the waist across the narrowest part or the waist seam.
- Measure the hips across the widest part of the skirt, below the waist seam.
- Double each number and write it next to the dress's labelled size.
Remember that these are garment measurements, so they will be a few centimetres larger than your body measurements. Compare them only with other garment figures, never directly with a body size chart.
How does a UK dress size compare with EU and US sizes?
On most UK retailers' conversion charts, a UK 12 is an EU 40 and a US 8. ASOS, Hobbs and John Lewis all list the same pattern: add 28 to a UK size for the EU (French) size and take away 4 for the US size. German and Italian sizes use different offsets, so check the label carefully when buying from European brands.
Common mistakes to avoid
- Going by the label in your wardrobe. Sizes vary between shops, so a 12 elsewhere is not proof of a 12 here.
- Measuring the waist at your jeans' waistband. Low-rise waistbands sit on the hips; dress charts use the natural waist.
- Using a padded or minimiser bra. Either one changes the bust reading by enough to move you a size.
- Rounding down. If you sit between sizes, the larger one is easier to alter.
- Ignoring stretch. Jersey and stretch crepe are forgiving; woven cotton, linen and satin are not. Check the fabric before deciding between two sizes.
Need your measurements in inches as well? The cm to inches converter handles them instantly.
Frequently asked questions
How do I know my UK dress size?
Measure your bust, natural waist and hips, then find each on the retailer's size chart. For a fitted dress, choose the largest of the three sizes.
What measurements are a UK size 12?
It depends on the shop. ASOS lists a 93 cm bust, 75 cm waist and 98.5 cm hip; Hobbs lists 95 cm, 77 cm and 102 cm.
Should I size up or down if I am between sizes?
Size up, especially in non-stretch fabrics. A slightly loose dress can be taken in, but there is rarely enough fabric to let one out.
Which measurement matters most for a dress?
It depends on the style. Fitted dresses need all three; fit-and-flare dresses depend on bust and waist; shift dresses on bust and hips.
Do petite dresses use different sizes?
No. Petite ranges use the same size numbers and body measurements, but with shorter lengths for women of shorter height.
Sources
- ASOS women's dresses size guide: bust, waist and hip measurements for UK 4 to 18.
- Hobbs size guide: women's body measurements and petite height guidance.
- BSI: BS EN 13402-1 Size designation of clothes: standard definitions of bust, waist and hip girth.
- John Lewis international size conversion guide: UK, EU and US dress size equivalents.