Underwear Size Calculator

Our full size range in one place, with the body measurements behind every letter and number. ILARIA letters run a step larger than the American ones, which is the whole reason this page exists. Anything cut differently carries its own chart on its own product page.

Measure yourself in 4 steps

Use a soft tape measure over bare skin or a thin unpadded bra. Snug enough to stay put, loose enough that it never presses into you. All our charts are in inches and describe your body, not the garment.

Step 1 — Find your underbust
Step 2 — Measure your bust
Step 3 — Define your waist
Step 4 — Find your hips

Wrap the tape around your ribcage directly under your bust, keeping it level all the way round. Breathe out, then read the number.

Measure around the fullest part of your bust with the tape resting rather than pulling. Stand relaxed with your arms down.

Find the narrowest part of your waist, usually just above the navel, and measure there without holding your stomach in.

You'll need it for bodysuits, shapewear, and high-waist underwear.

Measure around the fullest part of your hips with your feet together, keeping the tape parallel to the floor.
This number is your hip measurement, used for bodysuits, briefs, thongs, and shaping pieces.

SmartSize_size_chart_a6b851ef-8a2f-4d5d-b553-1aec304b1a31 - ILARIA Intimates

SmartSize_size_chart_f9aa7196-5306-4a26-a074-ccf32dba795b - ILARIA Intimates

Not sure? Let the fit recommender do it

Type your measurements in and our fit recommender gives you a size for the piece you are looking at, the same tool that sits on every product page.

Size charts

Bras are read from two measurements, bodysuits and shapewear from three, underwear from two. Each style is cut on its own pattern, so read the chart for the piece you want rather than assuming your usual letter.

Bras

Bands 34 to 44 · cups D to G

Your band comes from your underbust. Your cup comes from your bust minus your underbust: 7 inches is a D, 8 a DD, 9 a DDD, 10 a G. Pick your size below to see the bras that come in it.

Band	D	DD	DDD	G
34	34D	34DD	34DDD	34G
36	36D	36DD	36DDD	36G
38	38D	38DD	38DDD	38G
40	40D	40DD	40DDD	40G
42	42D	42DD	42DDD	42G
44	44D	44DD	44DDD	44G

Our alpha-sized bras

SmoothForm wireless bra size chart, sizes M to 5XL with underbust and bust measurements and the underwire band and cup each size matches

SmoothForm and the Everyday V-Neck come in letters instead of a band and a cup, and both run one size smaller than standard U.S. alpha sizing. If you are normally a US small, order M.

Neither is made in S, and SmoothForm is the one that runs to 5XL. The last column of the chart gives the underwire band and cup each letter matches, so you can work from a size you already know.

M L XL 2XL 3XL 4XL 5XL

Bodysuits & shapewear

Most of our bodysuits are cut on one grid. Two pieces sit outside it: the CurveHold mid-thigh bodysuit is cut close and runs about a size smaller, and StreetForm is a top rather than a shaping piece. Between two sizes, take the larger one.

S

M

L

XL

2XL

Bodysuit and shapewear charts

The standard grid. SmoothLayer, ZipSculpt and SoftSculpt are all cut to it.

CurveHold Mid-Thigh Bodysuit. Firm and cut close, so it runs about a size smaller.

StreetForm Bodysuit. Worn as a top, so the hip is cut loose and left off the chart.

Underwear & briefs

Briefs, shorts and thongs are read from your waist and your hips only. The everyday pairs share one grid. The CurveHold shaping thong is cut deliberately larger, because a firm pair has to stretch over more, so it keeps its own chart.

Underwear charts

The standard grid. Everyday Briefs and EverydayEase Shorts are cut to it, and SoftLine comes in one size.

CurveHold High-Waisted Thong. Firm tummy smoothing, cut larger than the everyday pairs.

A few things the charts do not tell you

Sizing has some quirks that catch women out, and three of them are worth knowing before you order.

Sister sizes. Go down a band and up a cup, or up a band and down a cup, and the cup volume stays roughly the same. A 38DD and a 40D hold a similar amount, they just sit differently on your ribs. Useful when your band size is between two numbers.
Our letters run larger than the American ladder. Measure yourself rather than converting the size you usually buy, because a 36D here is not the volume a 36D is elsewhere.
Between two sizes, take the larger one. This holds at every level of shaping. Sizing up on a firm piece to make it comfortable is the one exception that backfires, because a shaper that slips does not smooth.

Read the longer version, with the numbers worked through

FAQs

My measurements land between two sizes. Which one do I take?

The larger one. A band you can breathe in will always be better than a band that leaves a mark, and if it turns out too loose your first exchange is free.

My size here is different from my size at other shops. Did I measure wrong?

Almost certainly not. The same body reads as a 36D in one sizing system and a 32G in another, and both labels are describing exactly the same bra. Measure yourself once and use our chart rather than the number on your old label.

Should I measure with a bra on or off?

Over bare skin or a thin unpadded bra. A padded or push-up bra adds to your bust measurement and will send you a cup size too large.

Why is a size L different in each bodysuit?

Because each style is cut on its own pattern. A SmoothLayer L covers a 35 to 41 inch bust and a SoftSculpt L covers 40 to 44, so the letter alone will not tell you which one fits. Read the chart for the piece you want.

What if I am a G cup or larger?

Our underwire styles go to a G cup on bands 34 through 44. If your difference works out at more than ten inches, write to us before ordering and we will tell you honestly whether we have something that will work.

Does the level of shaping change which size I should order?

No. Order your measured size in every level. Firmer pieces feel tighter because of how they are constructed, and sizing up to compensate leaves you with something that slips instead of smooths.

My size changed after a baby, or through menopause. How often should I measure again?

Whenever something stops feeling right, and at least once a year. It takes two minutes and it is the single thing most likely to fix a bra that has started to annoy you.