How to Measure Bust, Waist and Hips

Good numbers need a good tape. Use a soft tape measure, stand relaxed and keep the tape level, meaning parallel to the floor, all the way around your body.

Bust

Stand naturally and breathe normally. Wrap the tape around the fullest part of your bust. Check that it stays level across your back and does not climb or sag.

Waist

Your natural waist is not where your trousers sit. Bend slightly to one side. The crease that forms is your natural waistline. Measure around that point with the tape level and comfortably loose.

Hips

Stand with your feet together. Measure around the fullest part of your hips and seat. This is usually lower than people expect.

Precision

Record each number to the nearest half inch, or 0.5 cm. A quarter inch rarely changes a size, but a sloppy inch can.

Pro-Tip: Measure over underwear or a thin layer, then ask a friend to check the tape is level at the back. A sagging tape in the rear is the most common reason two measurements of the same person disagree.

How the Calculator Chooses Your Size

The calculator matches each measurement to its nearest size in the chart, then gives you the largest of the three. That rule comes from how dresses work. A dress must close over your biggest measurement, so that measurement decides. Take a bust of 34 in, a waist of 26 in and hips of 39 in. Bust and waist both land on US 6. Hips land on US 8. The answer is US 8, because the dress has to pass over your hips.

Ties go up. If a measurement sits exactly halfway between two sizes, the calculator picks the larger one. It also rounds every entry to the nearest quarter inch before matching, so tiny differences do not flip your size at random.

Pro-Tip: When bust and hips fall in different sizes, buy for the larger one and tailor the smaller. Taking in a waist or a bust is a routine job. Letting out hips is often limited by the seam allowance.

Dress Size Conversion Chart: US, UK, EU and AU

UK 12 is US 8, EU 40 and AU 12. Going the other way, EU 40 is also US 8. The chart below lists every size the calculator covers, with body measurements in inches and centimeters.

US	UK	EU	AU	Letter	Bust in (cm)	Waist in (cm)	Hips in (cm)
2	6	34	6	XS	31 (78.5)	23¾ (60.5)	33¾ (86)
4	8	36	8	S	32 (81)	24¾ (63)	34¾ (88.5)
6	10	38	10	S	34 (86)	26¾ (68)	36¾ (93.5)
8	12	40	12	M	36 (91)	28¾ (73)	38¾ (98.5)
10	14	42	14	M	38 (96)	30¾ (78)	40¾ (103.5)
12	16	44	16	L	40 (101)	32¾ (83)	42¾ (108.5)
14	18	46	18	L	43 (108.5)	35¾ (90.5)	45¾ (116)
16	20	48	20	XL	45½ (116)	38½ (98)	48½ (123.5)
18	22	50	22	none	48 (122)	41 (104)	51 (129.5)
20	24	52	24	none	50½ (128)	43½ (110)	53½ (135.5)

Dress size conversion chart for US, UK, EU and AU sizes. Values follow ASOS’s published women’s size chart.

Two notes. US 18 and 20 have no letter size here, because the source chart stops at XL. And letter sizes vary between retailers, so use them as a rough guide only.

US vs UK vs EU vs AU Sizes: Why the Numbers Differ

The numbers differ because each region built its own scale. On this chart the pattern is simple. UK is US plus 4. AU matches UK. EU is UK plus 28. So US 8 becomes UK 12, AU 12 and EU 40. EU is the slippery one. Some charts show EU 38 for US 8, which is two lower than the EU 40 above. Both exist because countries inside Europe follow different conventions. If a retailer’s chart disagrees with this one, trust the retailer for that purchase.

There is a deeper reason for the mismatch. Standards bodies publish body measurement tables, not conversion formulas. The US has ASTM D5585 for misses sizes. Europe has EN 13402, which works in centimeters. A table of body measurements is not the same thing as a size label, so brands interpret them differently.

Pro-Tip: Ordering from abroad? Use the size chart for the shop’s own region and compare your three measurements to its numbers. Do not convert from memory. One wrong “plus 4” costs a return.

Why Your Size Changes Between Brands

Brands set their own fit, so one body can wear a 10 in one shop and a 12 in another. This calculator follows one published chart, so it gives you a sound starting point and nothing more. Use it to narrow the field. Then open the brand’s size chart and compare your bust, waist and hips with its numbers. If you land between two sizes, let the fabric decide. Stretch knit forgives the smaller size. Stiff woven cloth does not. Know the limits before you rely on the result. The tool covers US sizes 2 to 20 (UK 6 to 24). It does not cover petite or children’s fits. It ignores height. It sizes women’s dresses only, so jeans and tops need their own measurements.

Sizing for Trail and Travel Days

Outdoor clothing asks more of a fit than a dinner dress does. You will reach, climb, sit on rocks and wear layers. Size for movement first, and check that the dress or skirt does not bind at the hip when you step up.

Pro-Tip: A pack hip belt sits right on your hips, so your hip measurement matters most for anything worn under it. Choose a dress or skirt with room there, or you will feel every seam by mile three.

If you are shopping abroad for boots too, convert shoe sizes with the Shoe Size Calculator.

FAQs

What is my dress size from bust, waist and hips?

Match each measurement to a size chart and take the largest. For example, 36 in bust, 28 in waist and 39 in hips is US 8.

Is UK 12 the same as US 8?

Yes, on this chart. UK sizes run four higher than US sizes.

Which measurement decides my dress size?

The largest one. If your hips match a bigger size than your bust, buy for your hips.

How accurate is a dress size calculator?

It gives a starting size. Brand charts differ, so check the brand’s own chart before you buy.

Why does EU size sometimes differ by two?

Countries follow different EU conventions. Some charts show EU 38 for US 8, while this chart shows EU 40.

Does the calculator work above US 20?

No. It covers US 2 to 20 (UK 6 to 24) and does not size above US 20.