Advanced Bra Size Calculator

Uses modern sizing logic to find your perfect international fit.

1

Your Measurements

How to measure: Wear a non-padded bra. Measure your Snug Underbust directly beneath your breasts. Measure your Fullest Bust across the fullest part of your chest.
Inches (in)
Centimeters (cm)
in
in
2

Breast Shape (Optional)

Round
Bell Shape
Side Set
East West
Tear Drop
Asymmetric
Please ensure your Bust measurement is larger than your Underbust.

Your International Sizes

UK --
USA --
AU/NZ --
EU --
Cup Size (Difference)
--
Sister Size (Tighter Band)
--
Sister Size (Looser Band)
--
Selected Shape
Not Selected

✓ Quick Fit Checklist
  • The Band: Should sit snug and parallel to the floor. If it rides up your back, the band is too large.
  • The Gore: The center part between cups should sit completely flat against your breastbone.
  • The Cups: Tissue should be fully encased. If there is wrinkling, the cup is too big. If you spill over, it's too small.

Common Bra Sizing Questions

Cup sizes increase alphabetically. Therefore, D is bigger than C, and C is bigger than B. Keep in mind that a cup's actual visual volume also depends heavily on the band size it is attached to!
A 32C is bigger than a 32B. While the band size (32) remains identical, the "C" cup indicates a larger difference (typically 3 inches) between your fullest bust and underbust measurements compared to a "B" cup (which is a 2-inch difference).
The number "34" exclusively refers to your band size, meaning it is designed for a snug underbust measurement of approximately 33 to 34 inches. The total volume of the bra cannot be determined without the cup letter (for example, a 34A is much smaller overall than a 34G).
You calculate your size using two measurements: your snug underbust (which provides your band size) and your fullest bust. You then subtract your underbust from your bust measurement. Each inch of difference generally corresponds to a cup size up (1" = A, 2" = B, 3" = C). The easiest way is to simply enter your measurements into our automated calculator above!
Plus Size Bra Sizing Guide

Finding the perfect bra shouldn't feel like guessing lottery numbers. Yet, statistics show that nearly 80% of women are walking around right now wearing the wrong size. Whether you're dealing with straps that dig in, a band that constantly rides up your back, or cups that just don't quite fit your natural shape, the struggle is incredibly real. That’s exactly why we designed this comprehensive tool.

Our advanced calculator takes the mystery out of lingerie shopping. It doesn't just stop at giving you a standard number; it incorporates modern sizing logic, considers your unique breast shape, and instantly translates your measurements into a global sizing passport. Stop settling for "good enough" and discover what true, tailored comfort feels like.

How It Works: A Reliable Bra Size Converter

Calculating your accurate size boils down to a simple mathematical relationship between two key measurements. While vintage sizing methods often asked you to add extra inches to your band measurement (a trick from the days before elastic fabrics!), our tool uses the modern "+0 method." This means your actual ribcage measurement directly dictates your band size, resulting in a much more supportive and secure fit.

The Core Calculation

  • The Band Size: Derived directly from your snug underbust measurement. If you measure 34 inches, your band size is a 34.
  • The Cup Size: This is the difference between your fullest bust measurement and your band size. Every inch of difference generally represents one cup letter up (e.g., 1 inch = A, 2 inches = B, 3 inches = C, etc.).

Bra Size Calculator in Inches vs. Bra Size Calculator in cm

We know that people measure differently depending on where they live and what tools they have at home. That's why our tool seamlessly functions as both a bra size calculator in inches and a bra size calculator in cm.

If you prefer the metric system, you can easily toggle the calculator to centimeters. The logic remains the same, but the conversion is handled instantly behind the scenes. As a general rule of thumb when using a bra size converter:

  • 1 inch = 2.54 centimeters.
  • When calculating in cm, cup sizes usually progress with every 2-3 cm difference rather than every 1 inch.

Bra Size Calculator for Plus Size

Shopping for fuller busts requires precise measurements because support becomes even more critical. A generic bra size calculator for plus size individuals often fails because it doesn't account for sister sizing or structural shape. Our calculator excels here by providing your exact cup depth alongside sister size options.

For plus sizes, we highly recommend paying close attention to the "Sister Size (Tighter Band)" recommendation. A tighter band often provides the essential lift needed for heavier tissue, taking the strain off your shoulders and back.

International Bra Size Conversion Charts

Have you ever found a gorgeous piece of lingerie online, only to realize the brand uses a completely different sizing system? A 36G in the UK is drastically different from a 36G in the US or Europe. Below, we break down how sizes differ globally so you can shop international brands with complete confidence.

Bra Size Calculator UK vs. Bra Size Calculator USA

The UK and US share the same band sizing system (measured in inches). However, once you pass a D cup, the lettering systems diverge significantly. The UK uses double letters frequently (DD, E, F, FF, G, GG), while the US system tends to either repeat letters (DD, DDD, DDDD) or progress linearly (DD, F, G, H).

If you are using a bra size calculator UK and get a 34FF, a bra size calculator USA would translate that same physical volume to a 34H.

UK vs. USA Cup Conversion Chart

Difference (Inches) UK Cup Size USA Cup Size
1"AA
2"BB
3"CC
4"DD
5"DDDD / E
6"EDDD / F
7"FG
8"FFH
9"GI
10"GGJ

Bra Size Calculator Europe

If you are buying from luxurious French or everyday German brands, you need to understand EU sizing. A bra size calculator Europe operates entirely in centimeters. The band size in the EU is your underbust measurement in cm (rounded to the nearest 5). For example, a 75 cm underbust is a 75 band.

EU Band Size Conversion

UK / USA Band EU Band French (FRA) Band
306580
327085
347590
368095
3885100
4090105
4295110

Bra Size Calculator Australia

Australian sizing aligns its band sizes with standard dress sizes rather than inches. If you wear a size 12 top, you'll likely wear a 12 band. A bra size calculator Australia typically subtracts 22 from the UK/USA band size to find the Aussie equivalent (e.g., 34 - 22 = 12). Fortunately, Australian cup sizing generally follows the UK standard up to an E cup.

Australian Size Conversion Chart

UK / USA Band Australian Band Example Full Size (UK to AUS)
30830D = 8D
321032DD = 10DD
341234E = 12E
361436F = 14F
381638G = 16G
401840H = 18H

Real User Reviews

Don't just take our word for it! Here is what real users are saying after using our advanced fit tool to finally end their lingerie frustrations.

S
Sarah Jenkins
✓ Verified User
★★★★★

"I honestly thought I was a 36C my entire adult life. The calculator put me at a 32E and suggested a balconette style for my shape. I ordered one just to test it out and I am speechless. No more straps falling down, and my posture looks entirely different!"

M
Michelle R.
✓ Verified User
★★★★★

"The bra size calculator for plus size is a game changer. Most calculators max out or give me crazy proportions. This gave me my accurate UK size (38GG) and the sister sizing helped me find a sports bra that actually locks everything down."

E
Emma Thompson
✓ Verified User
★★★★☆

"I love how it breaks down the international sizes. I do a lot of online shopping from European boutiques, and the bra size calculator Europe conversion was spot on. A 75F fits me perfectly."

C
Chloe W.
✓ Verified User
★★★★★

"I live in Sydney and the bra size calculator Australia conversions are incredibly helpful. I always get confused converting US inches to our dress-size bands. Now I know I'm a solid 14DD. Highly recommend bookmarking this page."

J
Jessica K.
✓ Verified User
★★★★★

"Finally, a tool that includes breast shape! I always had gaping at the top of my cups. Clicking 'Tear Drop' shape gave me the fit tip to try plunge styles instead of full coverage. It completely solved my issue."

A
Amanda B.
✓ Verified User
★★★★★

"Super easy to use. I like being able to switch the bra size calculator in cm because measuring tapes in my house are all metric! The results were instant and gave me my sister sizes to take to the store. 5 stars."

© All Rights Reserved.