Bandeau One Piece Swimsuit

HauteFlair Editorial Reference Last reviewed: June 4, 2026 Bra Sizing

The complete HauteFlair bra size chart. This is the persistent reference for the master US size chart, what each cup letter actually means, sister-size relationships, and the two-step measurement that produces an accurate size. Most wearers are in the wrong size — usually a too-loose band and too-small cups — so start with a fresh measurement, then read the chart.

✦ Quick Answer — How to Use This Chart

Measure two things: your band (snug under the bust) and your bust (across the fullest point).
Subtract band from bust. Each inch of difference is one cup letter — 1″ A, 2″ B, 3″ C, 4″ D, 5″ DD.
Pair your band number with your cup letter. A 32″ band with a 36″ bust is a 32D.
A cup letter is a difference, not a fixed volume — a 32D and a 36D are different cup sizes.
Between sizes? Use a sister size — same cup volume, one band over.
Re-measure every 6–12 months. Brand fit varies; treat the chart as a starting point.

Want it done for you? Enter two measurements and our bra size calculator returns your size instantly — then come back to read the chart.

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How to Measure Your Bra Size

Two measurements with a soft tape, basic subtraction, a moment to interpret — about five minutes. Measure over a thin, unlined bra (or no bra for the band), and keep the tape parallel to the floor.

Soft measuring tape laid out for taking bra band and bust measurements at home — Use a soft cloth tape — keep it level and snug, never tight.

1. Band Measurement

Wrap the tape snugly around your ribcage directly under the bust, parallel to the floor, on the exhale. Round to the nearest even inch — bands come in even sizes only (28, 30, 32, 34…).

2. Bust Measurement

Wearing an unlined, non-padded bra, wrap the tape around the fullest point of the chest, parallel to the floor, snug but not compressing. For a C cup and above, lean to 90° while measuring.

3. Subtract

Bust minus band, in inches. Each inch of difference is one cup letter: 1=A, 2=B, 3=C, 4=D, 5=DD, 6=DDD/F, 7=G. Round to the nearest whole inch.

4. Combine

Pair your band number with your cup letter. A 33″ band (rounds to 32) with a 36″ bust (4″ difference) gives a 32D. A 36″ band with a 39″ bust gives a 36C.

✦ The +4 Method Is Outdated

Older guides told you to add four inches to your underbust to find the band. Don't. Modern band elastic is engineered for the direct underbust measurement — adding inches creates a too-loose band, the leading cause of bra mis-fit.

For the full step-by-step with troubleshooting, see how to measure your bra size at home.

The Master US Bra Size Chart

Find your underbust measurement down the left column, then read across to your bust measurement. Where they meet is your size. The row gives you the band; the cup letter is the bust-to-band difference.

Underbust (Band)	A (+1″)	B (+2″)	C (+3″)	D (+4″)	DD (+5″)	DDD/F (+6″)	G (+7″)
28″	28A · 29″	28B · 30″	28C · 31″	28D · 32″	28DD · 33″	28DDD · 34″	28G · 35″
30″	30A · 31″	30B · 32″	30C · 33″	30D · 34″	30DD · 35″	30DDD · 36″	30G · 37″
32″	32A · 33″	32B · 34″	32C · 35″	32D · 36″	32DD · 37″	32DDD · 38″	32G · 39″
34″	34A · 35″	34B · 36″	34C · 37″	34D · 38″	34DD · 39″	34DDD · 40″	34G · 41″
36″	36A · 37″	36B · 38″	36C · 39″	36D · 40″	36DD · 41″	36DDD · 42″	36G · 43″
38″	38A · 39″	38B · 40″	38C · 41″	38D · 42″	38DD · 43″	38DDD · 44″	38G · 45″
40″	40A · 41″	40B · 42″	40C · 43″	40D · 44″	40DD · 45″	40DDD · 46″	40G · 47″
42″	42A · 43″	42B · 44″	42C · 45″	42D · 46″	42DD · 47″	42DDD · 48″	42G · 49″
44″	44A · 45″	44B · 46″	44C · 47″	44D · 48″	44DD · 49″	44DDD · 50″	44G · 51″

Format: size · bust measurement in inches. Read left to right — a 32″ underbust with a 36″ bust = 32D.

Measuring tape positioned to find cup size from the bust and band difference

Bra Cup Sizes Explained

The single most misunderstood thing on any bra chart: a cup letter is not a fixed volume. It's the difference between your bust and your band. That's why a 32D and a 36D are not the same cup size — the 36D holds more, because it sits on a bigger band. The cup-size chart below shows what each difference means.

Bra cup size reference flatlay showing how cup volume changes across sizes

Bust − Band	US Cup	What it means
1″	A	One inch of projection beyond the ribcage.
2″	B	The most common starting estimate — often too small once the band is corrected.
3″	C	The most-shopped cup overall. See C cup size explained.
4″	D	Last cup that's identical across US, UK, and EU systems.
5″	DD	Where US and UK sizing begins to diverge. See DD cup size explained.
6″	DDD / F	US doubles up (DDD); UK and EU continue the alphabet.
7″	G	Full-bust territory — band fit matters most here.

✦ Same Letter, Different Volume

Because the cup is a difference and not an absolute, two bras with the same letter on different bands hold different amounts. This is the whole basis of sister sizing — and why the size on your old bra is a poor guide to a new brand.

Sister Size Reference

Sister sizes share the same cup volume on a different band. They solve the most common mis-fit pattern (band wrong, cup right) and roughly triple your shopping range. Going up one band and down one cup letter gives a looser-band sister; going down one band and up one cup gives a tighter-band sister. (For the deep dive, see sister sizes explained.)

Sister Down (tighter band, larger cup)	Your Size	Sister Up (looser band, smaller cup)
30D	32C	34B
30DD	32D	34C
32C	34B	36A
32D	34C	36B
32DD	34D	36C
32DDD	34DD	36D
34C	36B	38A
34D	36C	38B
34DD	36D	38C
36D	38C	40B
36DD	38D	40C

Have your size and sister sizes? Shop the full range — every product page lists sister-size pairings so the trio is always one click away.

Shop All Bras →

International Sizes at a Glance

Shopping a UK, European, or Japanese brand? Cup letters match through D, then diverge — and bands switch from inches to centimeters. Here's the quick view for the most common sizes; the full country-by-country charts, the cm conversions, and an interactive converter live on the conversion page.

US	UK	EU	FR / ES	AU / NZ	JP
32C	32C	70C	85C	10C	70C
34C	34C	75C	90C	12C	75C
34D	34D	75D	90D	12D	75D
34DD	34DD	75E	90E	12DD	75E
36C	36C	80C	95C	14C	80C
36D	36D	80D	95D	14D	80D

Shopping across borders? Get your size in all seven systems — US, UK, EU, French, Italian, Australian, and Japanese — with the full converter and cm charts.

Full Conversion Chart →

"A size chart is a starting point. Brand grading varies, body shapes vary, the same labeled size fits differently across pieces. Use the chart as a hypothesis — and use sister sizing to test it without committing to a wrong number."
— HauteFlair Fit Editorial Team

Frequently Asked Questions

How do I read a bra size chart?

Find your underbust (band) measurement down the left column, then read across to your bust measurement. Where they meet is your size. The band number comes from your underbust; the cup letter comes from the difference between bust and band — each inch of difference is one cup letter (1″ A, 2″ B, 3″ C, 4″ D, 5″ DD).

How do I measure my bra size at home?

Take two measurements with a soft tape. First, your band: snug around your ribcage directly under the bust, rounded to the nearest even inch. Second, your bust: across the fullest point, parallel to the floor. Subtract the band from the bust — each inch of difference is one cup letter. Combine the band number with the cup letter to get your size.

What do the cup sizes on a bra chart mean?

A cup letter is the difference between your bust and your band, not a fixed volume. A 1-inch difference is an A, 2 is B, 3 is C, 4 is D, 5 is DD, 6 is DDD/F. Because the cup is a difference, the same letter holds different volumes on different bands — a 32D and a 36D are not the same cup size.

What is a sister size on a bra chart?

Sister sizes share the same cup volume on a different band. Going up one band and down one cup letter gives a looser-band sister; going down one band and up one cup gives a tighter-band sister. From a 34C, the sisters are 32D and 36B. Try your charted size plus its two sisters when a new brand fits oddly.

Should I trust the size on my current bra?

Probably not. Most wearers are in the wrong size — usually a band that's too loose paired with cups that are too small. The most reliable starting point is a fresh home measurement, not the label of the bra you currently wear.

How often should I re-measure my bra size?

Every six to twelve months, or after weight changes, hormonal shifts, pregnancy, breastfeeding, or menopause. Even the monthly cycle can shift bust measurement by half a cup. Bra size is not a fixed identity.

Is the +4 method for finding my band size accurate?

No. The +4 method (adding four inches to your underbust) dates from when bra elastic was much less stretchy and is now considered outdated. It produces a band that's too loose — the leading cause of bra mis-fit. Use your direct underbust measurement, rounded to the nearest even number, as your band size.

Do all brands match the same size chart?

No. Cup pattern, wire shape, fabric stretch, and grading vary by brand, so a 34C from one brand can fit like a 32D from another. Treat any chart as a starting point, and try your size plus its two sister sizes when shopping a brand for the first time.

This page is for informational and educational purposes only. HauteFlair is not responsible for individual fit outcomes — bra sizing varies between brands and styles, and the figures in this chart reflect industry-standard grading, not contractual mappings. For best results, refer to each brand's specific size chart. Last reviewed: June 4, 2026.

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