👙 Bra Size Calculator

Q: Why is proper bra sizing so important?

Correct fit reduces pain, improves posture, prevents spillage or gaping, and makes clothes look better.

Q: How often should I measure for a new bra size?

Every 6 months or after 10+ lb weight change, pregnancy, or menopause.

Q: What are sister sizes and why do they matter?

They have the same cup volume but different band/cup combinations (e.g., 34C = 32D).

Q: Can I use this calculator if I’m between sizes?

Yes—it suggests primary and sister sizes for better shopping options.

Q: How does weight change affect bra size?

Gaining or losing weight often changes band and sometimes cup size.

Q: What’s the difference between US and UK cup sizes?

The tool provides conversions; UK sizing is commonly used internationally.

Q: Is this accurate for sports bras?

It gives a starting band/cup; sports bras often run tighter—size up if needed.

Q: Why does my bra size differ between brands?

Brands use vanity sizing and different shapes—always try on.

Q: Can teenagers use this calculator?

Yes, but growing bodies may change quickly—re-measure often.

Q: How do I know if my band is too loose?

It rides up in back; try a smaller band with sister cup.

Find your perfect fit with International sizing & sister sizes

1Measure

2Details

3Result

📏 Measurement Unit

Inches Centimeters

🎂 Age

🤰 Pregnant

Yes No

🍼 Breastfeeding

Yes No

📐 Underbust (Band) Measurement

📐 Overbust (Bust) Measurement

34C

Your Size

—

International Bra Size Converter

🇺🇸 US

—

🇬🇧 UK

—

🇪🇺 EU

—

🇦🇺 AU

—

🇫🇷 France

—

Sister Size Calculator

If your result is 34C, try these sister sizes:

⬇️ Sister Size (Down)

32D

⬆️ Sister Size (Up)

36B

Bra Size by Brand

Your size 34C across popular brands:

Brand	Your Size	Fit Note
N Nike	34C	True to size
V Victoria's Secret	34C	May need 34D
H H&M	34C	True to size
Z Zara	34C	True to size
C Calvin Klein	34C	Size up for comfort
T Triumph	34C	True to size

Breast Shape Guide

Identify your breast shape for better fit:

🔵

Round

Full all over, balanced

🔔

Bell

Fuller at bottom, narrower top

↔️

East West

Point outward, wider set

💪

Athletic

Muscular, less tissue

💧

Tear Drop

Slightly fuller at bottom

Recommended Bras

T-shirt BraSports BraBalconettePush Up

Support Level: High Comfort: Balanced

ℹ️ This calculator provides estimates based on standard sizing. For best fit, always try bras on or consult a professional fitter.

Guide

Underbust: Measure snugly around your ribcage, just below your bust.
Overbust: Measure loosely around the fullest part of your bust.
Band size is the underbust measurement rounded to nearest even number.
Cup size = difference between overbust and underbust (1 inch = 1 cup size).

📏 How to Measure

Use a soft measuring tape
Measure underbust snugly (exhale normally)
Measure overbust loosely across fullest part
Wear a non-padded bra while measuring

💡 Signs of Poor Fit

Band rides up → too loose
Spilling over cups → too small
Gaping at top → too large
Straps digging → need adjustment

📊 Cup Size Chart

Diff (in)	US/UK	EU
<1	AA	AA
1	A	A
2	B	B
3	C	C
4	D	D
5	DD/E	E
6	DDD/F	F
7	G	G
8	H	H

🌍 Band Equivalents

US/UK	EU	FR
28	60	75
30	65	80
32	70	85
34	75	90
36	80	95
38	85	100

How To Measure

Struggling with straps that slip, cups that gap, or bands that ride up is incredibly common—studies suggest up to 80% of women wear the wrong bra size, leading to discomfort, poor posture, and even back pain. UseToolsPro’s Bra Size Calculator uses standard measurement methods to deliver accurate band and cup recommendations, plus sister sizes and international conversions, so you can shop smarter and feel better every day.

How to Use the Bra Size Calculator

Getting the right bra size makes a huge difference in comfort and confidence. Our bra size calculator is simple, accurate, and gives instant results with sister size suggestions. All you need is a soft tape measure, a mirror, and 3-5 minutes. Wear a non-padded bra (or none) and stand relaxed in front of the mirror.

Wrap the tape measure snugly around your ribcage, just under your breasts. Keep it parallel to the floor and breathe normally. This is your underbust measurement. The calculator will round it to the nearest even band size (32, 34, 36, etc.).

Measure around the fullest part of your breasts (usually at nipple level). Keep the tape level and comfortable — don't pull too tight. This is your bust measurement.

It subtracts your underbust from your bust to find the cup size (A, B, C, D, DD/E, etc.). You’ll also get sister sizes — same cup volume but different band/cup combos — which are very helpful when your perfect size is out of stock.

Measure twice and take the average
Avoid measuring over clothes or padded bras
Re-measure every 6 months or after weight changes, pregnancy, or menopause
Tell us your current bra problems (tight band, gaping cups, etc.) for better advice

      Ready? Select inches or cm, enter your measurements, and click “Calculate My Bra Size”. You can tweak any number and see updated results instantly. Try on bras in-store when possible because shape and brand can vary.
    

Visual Walkthrough: Real-World Sizing

Office Professional

32-Year-Old Office Professional

Consider a 32-year-old woman in Denver entering her measurements: underbust 29.5 inches, bust 35 inches, age 32, reporting occasional shoulder strap pain and cup gaping in current bras.

Recommended Size: 32D • Sister Sizes: 30DD / 34C

Measurement Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Current Measurements	29.5"	35"	32	D	30DD, 34C	Good volume, check band
Tighter Band (+1" snug)	30.5"	35"	32	DD	30E, 34D	Firmer support needed
Goal (Bust -1")	29.5"	34"	32	C	30D, 34B	Improved everyday comfort
Looser Band	31.5"	35"	34	C	32D, 36B	Alternative for comfort

Teenager

How a 16-Year-Old Teen Found Her Perfect First Bra Size

Riya, a 16-year-old from Mumbai, entered her measurements: underbust 26.5 inches, bust 31.5 inches. She was struggling with cup gaping during school hours.

Recommended Size: 28B • Sister Sizes: 26C / 30A

Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Current	26.5"	31.5"	28	B	26C, 30A	Perfect for school & growth
After Growth	27.5"	32.5"	28	C	26D, 30B	Ready for next stage

Working Woman

32-Year-Old Working Woman Solves Daily Bra Discomfort

A 32-year-old professional in Delhi inputs: underbust 29.5 inches, bust 35 inches, and reports shoulder pain & cup gaping.

Recommended Size: 32D • Sister Sizes: 30DD / 34C

Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Current	29.5"	35"	32	D	30DD, 34C	Good volume
Tighter Band	30.5"	35"	32	DD	30E, 34D	Better support for office

New Mother

New Mom Discovers Right Bra Size After Pregnancy

Priya, 29-year-old new mother, entered: underbust 31 inches, bust 37 inches, mentioning postpartum changes.

Recommended: 34DD • Sister Sizes: 32E / 36D

Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Current Postpartum	31"	37"	34	DD	32E, 36D	Great for nursing
3 Months Later	30.5"	35.5"	32	D	30DD, 34C	Body recovering

Plus Size

Plus Size Woman Finds Comfortable & Supportive Bra Size

Neha, 38, inputs: underbust 37 inches, bust 44 inches, struggling with tight bands and shoulder pain.

Recommended Size: 38G • Sister Sizes: 36H / 40F

Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Current	37"	44"	38	G	36H, 40F	Strong support
Comfort Focus	38"	44"	40	F	38G, 42E	All-day ease

Athlete

Young Athlete Gets Perfect Sports Bra Size

Anika, a 26-year-old fitness enthusiast, enters: underbust 28.5 inches, bust 33 inches, and selects high-activity sports preference.

Recommended: 30C • Sister Sizes: 28D / 32B

Scenario	Underbust	Bust	Band	Cup	Sister Sizes	Fit Notes
Training Days	28.5"	33"	30	C	28D, 32B	High impact ready
Competition Mode	28"	32.5"	28	D	26DD, 30C	Maximum hold

      Bonus Tip: You can try all these real-life examples directly in the calculator and see live results!
    

Interpreting Your Bra Size Results Effectively

The Bra Size Calculator provides these key outputs:

Band Size: Numerical underbust-based measurement (e.g., 32, 34)
Cup Size: Letter designation based on bust-underbust difference
Recommended Size: Primary suggestion
Sister Sizes: Alternative combinations with equivalent volume
Fit Guidance: Notes on common issues and adjustments
International Conversions: UK, EU, FR, AU equivalents

View results as a strong starting point rather than absolute truth—different brands vary in sizing. A well-fitting bra should feel supportive without digging in, with the band level across your back and cups fully containing breast tissue without spillage or gaping.

Limitations: This uses standard circumference methods and is an estimation tool. Shape, breast density, and brand variations affect final fit. For persistent pain, asymmetry, or post-surgery needs, consult a certified fitter or healthcare provider.

Bra Size Reference Guide

Use this chart to understand cup sizes across different countries. The cup size is determined by the difference between your bust and underbust measurements.

Difference (Bust - Underbust)	US / UK	EU / International	France / Spain	Australia / NZ	Japan	Italy
0–1 inch (0–2.5 cm)	AA / A	AA / A	AA / A	AA / A	A	AA / A
2 inches (5 cm)	B	B	B	B	B	B
3 inches (7.5 cm)	C	C	C	C	C	C
4 inches (10 cm)	D	D	D	D	D	D
5 inches (12.5 cm)	DD / E	E	E	DD	E	DD
6 inches (15 cm)	DDD / F	F	F	E / F	F	E
7 inches (17.5 cm)	G	G	G	F / G	G	F
8 inches (20 cm)	H	H	H	G / H	H	G
9 inches (23 cm)	I	I	I	H / I	I	H
10+ inches (25+ cm)	J and above	J and above	J and above	I and above	J and above	I and above

Note: Band sizes are usually the same across most countries (even numbers like 32, 34, 36), but cup sizes can vary slightly by brand. Always try on bras when possible as fit also depends on breast shape.

Bra Size Variations by Popular Brands

Brand	Band Fit	Cup Fit	Best For	Common Advice
Victoria's Secret	Snug / Runs small	More projected	Fashion & Push-up	Size up in band
Calvin Klein	True to size	Shallower cups	Everyday comfort	Good for average shapes
Nike	Firm	Compressed	Sports & High impact	Choose based on activity
Triumph	True to size	Good coverage	Full coverage & Support	Reliable for bigger cups
H&M	Runs loose	Shallower	Budget & Fashion	Size down in band
Zivame	True to size	Deeper cups	Indian body types	Excellent for plus size
Clovia	Slightly snug	Good variety	Everyday & Fashion	Check reviews
Jockey	Very comfortable	Relaxed fit	Daily wear	Great for beginners

Breast Shape Guide: Find Your Shape & Best Bra Style

Knowing your breast shape helps choose the most comfortable and flattering bra styles.

Breast Shape	Description	Best Bra Styles	Recommended Brands
Round	Full and equally rounded on top and bottom	Balconette, Demi, Push-up	Victoria's Secret, Calvin Klein, Zivame
Bell	Fuller at the bottom with less volume on top	Full Coverage, Balconette, Plunge	Triumph, Zivame, Clovia
East West	Breasts point outwards; nipples face away	Front-closure, Side-support, T-shirt bras	Calvin Klein, Jockey, H&M
Athletic	More muscle tissue, wider chest, smaller breasts	Sports bras, Compression, Bralettes	Nike, Triumph, Jockey
Teardrop	Fuller at the bottom, gently sloping from top	Full Coverage, Contour, Minimizer	Triumph, Zivame, Calvin Klein

Round

Bell

East West

Athletic

Teardrop

Note: Most women have a combination of shapes or one breast slightly different from the other — this is completely normal!

Trust in Our Bra Size Calculations

The calculator applies widely used industry-standard circumference methods (including US/UK sizing conventions) cross-referenced with common brand charts and fitting guidelines from lingerie experts.

Assumptions include standard adult anatomy and accurate user measurements. Individual breast shape, firmness, and brand inconsistencies mean real-world fit may require trying on. This is an educational estimation tool. For best results, combine with professional fittings.

Common Mistakes to Avoid When Measuring Bra Size

1. Using the Wrong Tape Measure

Using a metal tape or string that stretches gives inaccurate results.

Tip: Always use a soft cloth or plastic tape measure.

2. Measuring with Loose Tape

Keeping the tape too loose, especially around the underbust.

Tip: Keep the tape snug but comfortable — you should be able to fit one finger underneath.

3. Wearing the Wrong Bra

Measuring over a padded or push-up bra.

Tip: Measure without a bra or wearing a non-padded, thin bra.

4. Bad Posture While Measuring

Slouching, leaning forward, or not standing straight.

Tip: Stand straight but relaxed in front of a mirror with shoulders back.

5. Measuring Over Clothes

Measuring while wearing thick clothes or multiple layers.

Tip: Always measure directly on bare skin or over very thin clothing.

6. Other Frequent Errors

Using old measurements
Measuring during menstrual cycle
Ignoring sister sizes
Not re-measuring after weight changes or pregnancy

      Pro Tip: Take measurements twice and average them. This simple habit can dramatically improve accuracy.
    

20 Bra Size Questions