How do I measure my bra size at home?

To measure your bra size at home: (1) Wrap a soft tape snugly around your ribcage just under your bust — this is your band measurement. (2) Wrap the tape around the fullest part of your bust — this is your bust measurement. (3) Your band size is your under-bust rounded to the nearest even number. (4) Cup size = bust minus band. Each 1-inch difference equals one cup size. For example, 34 band + 3-inch difference = 34C.

What is the ABTF method and is it better than the traditional method?

The Modern (ABTF) method uses your actual under-bust measurement rounded to the nearest even number with no padding. The Traditional method adds 4 inches to this measurement. The ABTF method is recommended by professional fitters today because modern bras are made with stretch fabric that provides support without the extra band length. Most women find the ABTF method produces a better-fitting, more supportive band.

What are sister sizes in bra sizing?

Sister sizes are bra sizes with the same cup volume but different band-to-cup combinations. For example, 34C, 36B, and 32D are sister sizes — they contain the same amount of cup volume. If a 34C band is too tight, a 36B will have the same cup volume on a looser band. If the band is too loose, a 32D has the same cup volume on a tighter band.

How do US and UK bra sizes differ?

US and UK bra bands are sized identically. Cup sizes are the same up to D. From DD upward they diverge: US DD = UK DD, US DDD/F = UK E, US G = UK F, US H = UK FF, US I = UK G, US J = UK GG, US K = UK H. When buying from UK brands like Panache, Freya, or Curvy Kate, always check the UK cup name for your size.

How do I convert US bra size to EU or French size?

EU band = US band × 2.54 rounded to the nearest 5 cm. So US 34 = EU 75 (34 × 2.54 = 86.36, rounded to 85 — but the standard lookup gives 75 because EU bands represent the actual under-bust in cm). French (FR) band = EU band + 15. So US 34C = EU 75C = FR 90C. Cup letters are the same across US, EU, and FR systems.

How often should I measure my bra size?

Remeasure every 6–12 months as a routine. Additionally remeasure after: significant weight change (10+ lbs / 4.5 kg), pregnancy (every 4–6 weeks during), 3–6 weeks postpartum once milk supply stabilizes, any surgery affecting the chest, or whenever your current bras stop fitting comfortably. Hormonal changes during menopause can also shift both band and cup size.

Why does my bra size differ between brands?

Bra sizing is not globally standardized. Each manufacturer uses its own fit model — a person with specific proportions used as the design reference — and applies different amounts of ease allowance (extra room built into the cup). For example, Victoria's Secret cups run small (size up 1 cup), while Savage X Fenty bands run large (size down 1 band). Always check brand-specific sizing guides and try on bras before purchasing when possible.

What bra size should I wear during pregnancy?

Breast size changes throughout pregnancy. In the first trimester, increase cup size by 1–2. By the second trimester, your band may increase by 2–4 inches — use bra extenders rather than buying many new bras. In the third trimester (week 36+), get fitted for nursing bras. Avoid underwire bras during pregnancy as they can restrict circulation. Remeasure every 4–6 weeks during rapid changes.

How do I find the right bra size for a full bust (DD+)?

For full-bust sizing (DD cup and above), use the ABTF method for the most accurate measurement. The key difference for full-bust fitting is underwire width — you need a wider underwire that fully encases all breast tissue from armpit to sternum. Brands specializing in full-bust sizes include Panache, Elomi, Freya, Curvy Kate, and Wacoal. Sister sizes are especially useful in the full-bust range where fewer sizes are available in-store.

What is the best bra size calculator method for plus size women?

Plus size women benefit most from the Modern (ABTF) method, which does not add artificial inches to the band. This produces a more accurate, supportive band measurement. Key considerations: (1) Extended sizes are available — bands 40–54 and cups up to N/P from specialty brands. (2) Full-bust plus size fits best with wide-set underwires and reinforced side panels. (3) Brands like Elomi, Goddess, and Torrid specialize in plus-size bra fitting. Always measure fresh — plus size bodies change shape more with weight fluctuation.

My bra band keeps riding up at the back — what size do I need?

A band riding up at the back means it is too loose. The band should stay level all the way around your torso. Go down one band size and up one cup size simultaneously (sister sizing) to maintain the same cup volume. A correct band lies parallel to the floor and allows two fingers to slide underneath at the back — no more.

What breast shape do I have and which bra style is best for my shape?

Identify your shape by observing: nipple direction, top-to-bottom fullness ratio, spacing between breasts, and how tissue sits on your chest. Round shape: most styles work. Teardrop: push-up or 3/4 cup. East-west (nipples point outward): plunge or T-shirt bra. Close-set: balconette, avoid deep-V. Wide-set: push-up with internal sling. Bell-shaped: full-coverage or minimizer. Pendulous (tissue sits low): full-coverage with deep lower cup. Asymmetrical: fit larger side, use removable padding in smaller cup.

How do I measure my bra size after weight loss or gain?

Remeasure after every 10 lb (4.5 kg) change. Weight loss typically reduces both band and cup size — breast tissue is mostly fat. After 20 lbs of loss, most women decrease 1–2 band sizes and 1–2 cup sizes. After 15+ lbs of gain, band size often increases more than cup size initially. Skin elasticity changes may require a different bra style at the new size — more lift and structured support are often needed.

What is the best bra size calculator for India sizing?

Indian (IN) bra sizing is identical to UK sizing. This calculator supports IN sizing directly. Select the IN region to see your size. For Indian brands: Zivame and Clovia follow international standard sizing accurately. Jockey India runs slightly small — size up 1 band if between sizes. For extended sizes in India, Zivame's marketplace stocks imported UK brands like Triumph and Enamor with domestic shipping.

Can I use a bra size calculator without a measuring tape?

Yes. Use a piece of string or ribbon: wrap it around your ribcage under your bust, mark the meeting point, then measure the string with a ruler. Repeat for your over-bust. Alternatively, a non-stretch waistband from clothing can work as a rough guide. For the most accurate result, a soft measuring tape is recommended and costs under $2 at most pharmacies or sewing stores.

Bra Size Calculator (UK, US, EU, IN) – Modern & Traditional Method

Free Bra Size Calculator 2026 — Modern (ABTF) & Traditional methods, sister sizes, breast shape guide, brand conversion chart, extended sizes AA–M.

How to Measure Your Bra Size

Quick formula:

Band size = under-bust measurement rounded to nearest even number | Cup size = bust minus band size (each 1 inch = 1 cup size up)

Measurement Method

NEW

Most online calculators still use the outdated Traditional (+4) method from the 1930s when bras had less stretch. The community at r/ABraThatFits (300k+ members) recommends the Modern / ABTF method for a more accurate, supportive fit.

Enter Measurements

Using Modern (ABTF) method ·

Sizing Region

Under-Bust (cm)

Measure around ribcage

Over-Bust (cm)

Measure fullest part

Breast Shape Guide

Exclusive

Your breast shape determines which bra styles work best — not just your size. Tap your shape below for personalised style recommendations.

How to identify your breast shape:

Stand without a bra and observe: the position of your nipples (forward, up, or down), how full the top vs. bottom of your breast is, how much space is between your breasts, and where tissue sits on your chest wall.

Fit Problem Diagnosis

Select a fit problem for a specific adjustment recommendation:

Bra Size Chart & Cup Guide

Cup sizes differ between US and UK from D upward — this extended chart covers sizes up to M cup.

Diff (inches)	US Cup	UK Cup	Category
0	AA	AA	Extra Small
1	A	A	Small
2	B	B	Medium
3	C	C	Full
4	D	D	Large
5	DD/E	DD	Extra Large
6	DDD/F	E	Double XL
7	G	F	Full Bust
8	H	FF	Full Bust+
9	I	G	Plus Bust
10	J	GG	Plus Bust+
11+	K–M	H+	Extended

Cup size = difference between bust and band measurements · US and UK cup names differ from D onwards

Band Size Guide

Compare band sizes across regions — includes extended sizes 28–54

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125

UK and India (IN) band sizes are identical. EU = underbust in cm. FR = EU + 15.

Brand Size Conversion Guide

Bra sizing is NOT standardized. The same labeled size fits differently across brands. Use this guide when shopping to avoid returns.

Why do bra sizes vary by brand?

Each brand uses its own "fit model" — a person with specific proportions used during design. The manufacturer also applies different amounts of "ease allowance" (extra room built into the cup). This is why a 34C in Victoria's Secret and a 34C in Panache can fit like two completely different sizes.

Brand	Region	Sizing Notes	Size Range
Victoria's Secret	US	Cups run small. Size up 1 cup (34C → 34D). Band runs true.	28–44, AA–DDD
ThirdLove	US	Half-cup sizes available. True to measurement. Use their fit quiz.	28–48, AA–I
Wacoal	US	True to size. Best for full-busted (D+). Excellent underwire placement.	30–46, A–H
Savage X Fenty	US	Band runs large. Size down 1 band. Cups are true.	32–46, A–42H
Panache	UK	UK sizing. Convert: UK 34DD = US 34DDD/F. Full-bust specialist.	28–44, A–L (UK)

Life-Stage Sizing Guide

Your bra size changes with life. Pregnancy, nursing, surgery, weight change, and menopause all affect sizing differently. Choose your situation:

Why Correct Bra Fit Matters

Studies show up to 80% of women wear the wrong bra size — wearing the right size is a health and comfort issue, not just a style one.

Benefits of Correct Fit

Better Comfort: No digging straps or underwires
Improved Posture: Reduces back and shoulder strain
Better Appearance: Clothes fit better with proper support
Health Benefits: Prevents neck pain, improves circulation
Boost Confidence: Feel comfortable and confident all day

Problems with Wrong Size

Shoulder Pain: Straps digging in or constantly slipping
Back Pain: Poor support leading to muscle strain
Skin Irritation: Marks, chafing, and uncomfortable rubbing
Breast Pain: Insufficient support causing discomfort
Poor Shape: Bulging, gaping, or unflattering silhouette

Ready to Find Your Perfect Fit?

Use our calculator above to find your correct bra size in seconds.

About This Bra Size Calculator

This calculator supports two measurement methods: the Modern (ABTF) method — which uses your actual underbust measurement rounded to the nearest even number — and the Traditional (+4) method used by older sizing guides and some US brands. Most professional fitters today recommend the modern method for better band support.

Cup size = bust − band size. Every 1-inch difference equals one cup size. The cup sizes differ between US and UK systems above D: US DDD/F = UK E, US G = UK F, and so on. Our extended chart covers cups from AA through M.

Sister sizes have identical cup volume but on a different band. If you're between sizes or a specific brand fits differently, try your sister size first before ordering a completely different size.

We support US, UK, EU, and IN (India) sizing. EU band = underbust in cm; FR = EU + 15. UK cups diverge from US at the DD level — always check the UK-specific name when ordering from UK brands like Panache or Freya.

Calculation Methodology & Sources

About this tool

This is a free online bra size calculator built on publicly documented sizing standards and community-verified measurement methods. All calculations are performed transparently using the formulas described below. No personal data is collected.

Modern (ABTF) method

Band size = under-bust rounded to the nearest even inch, with no addition. This is the method documented by the r/ABraThatFits community guide (300,000+ members) and is recommended for modern stretch-fabric bras which provide support without needing extra band length.

Traditional (+4) method

Band size = under-bust rounded to nearest even inch, then +4 inches added. This convention originates from the 1930s–1950s when bras were made from non-stretch fabric. As documented on Wikipedia — Bra size, this method is still used by some older US retail brands.

Cup size formula

Cup size = round(bust measurement − band size). Each 1-inch difference = one cup size up. US and UK cup names diverge at DD: US DDD/F = UK E, US G = UK F. International band conversions follow the Bratabase bra sizing systems guide: EU band = actual underbust in cm (rounded to nearest 5); FR = EU + 15.

Sister sizes

Sister sizes share identical cup volume on different band widths. Going up one band size requires going down one cup size to maintain the same volume — and vice versa. This is a standard principle explained by Brastop's sister size guide and the Busty Resources wiki.

⚠ Limitations

This tool provides an estimated starting size based on standard formulas. Individual fit preferences, breast shape, body posture, and brand-specific construction differences all affect real-world fit. Always try on bras before purchasing, or consult a professional fitter for the most accurate result.

Frequently Asked Questions

30 expert-answered questions covering every aspect of bra sizing — from basics to special situations competitors don't address.

Measurement Basics

6 questions

Modern vs Traditional Method

3 questions

Size Results & Sister Sizes

4 questions

Fit Problems

5 questions

Brand & Shopping Questions

4 questions

Life Stages & Special Situations

4 questions

Bra Types & Styles

4 questions

Still have a question? Our fit diagnosis tool above covers most bra fit problems.

Privacy & Data Security

All calculations are performed locally in your browser using JavaScript. No measurement data is sent to any server, stored in any database, or shared with any third party. Your body measurements are private.

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Bra Size Chart & Cup Guide

Cup sizes differ between US and UK from D upward — this extended chart covers sizes up to M cup.

Diff (inches)	US Cup	UK Cup	Category
0	AA	AA	Extra Small
1	A	A	Small
2	B	B	Medium
3	C	C	Full
4	D	D	Large
5	DD/E	DD	Extra Large
6	DDD/F	E	Double XL
7	G	F	Full Bust
8	H	FF	Full Bust+
9	I	G	Plus Bust
10	J	GG	Plus Bust+
11+	K–M	H+	Extended

Cup size = difference between bust and band measurements · US and UK cup names differ from D onwards

Band Size Guide

Compare band sizes across regions — includes extended sizes 28–54

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125

UK and India (IN) band sizes are identical. EU = underbust in cm. FR = EU + 15.

Brand

Region

Sizing Notes

Size Range

Victoria's Secret

Cups run small. Size up 1 cup (34C → 34D). Band runs true.

28–44, AA–DDD

ThirdLove

Half-cup sizes available. True to measurement. Use their fit quiz.

28–48, AA–I

Wacoal

True to size. Best for full-busted (D+). Excellent underwire placement.

30–46, A–H

Savage X Fenty

Band runs large. Size down 1 band. Cups are true.

32–46, A–42H

Panache

UK sizing. Convert: UK 34DD = US 34DDD/F. Full-bust specialist.

28–44, A–L (UK)

About This Bra Size Calculator

Calculation Methodology & Sources

About this tool

Modern (ABTF) method

Traditional (+4) method

Cup size formula

Sister sizes

⚠ Limitations

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125

UK / IN	US	EU	FR
28	28	60	75
30	30	65	80
32	32	70	85
34	34	75	90
36	36	80	95
38	38	85	100
40	40	90	105
42	42	95	110
44	44	100	115
46	46	105	120
48	48	110	125