Bra Size Calculator

Find your perfect fit with our easy-to-use calculator. Get your recommended size, discover your "sister sizes," and convert sizes for international brands.

The Comprehensive Guide to Bra Fitting and Sizing

Finding a bra that fits perfectly can feel like searching for a needle in a haystack. Studies indicate that nearly 80% of women wear the wrong bra size, leading to discomfort, poor posture, and even back pain. This calculator is designed to demystify the process, using industry-standard measurements to give you a reliable starting point for your perfect fit.

Why Fit Matters More Than Size

While "34B" or "36DD" are common sizes, they are just numbers. A true fit depends on the brand, the fabric, and the style of the bra. A well-fitted bra should feel like a second skin. The band provides 80% of the support, not the straps. If your straps are digging into your shoulders, it's a classic sign your band is too loose. Conversely, if the center gore (the piece of fabric between the cups) isn't lying flat against your sternum, your cup size might be too small.

The "Scoop and Swoop" Technique

When trying on a bra, the "Scoop and Swoop" method is essential. Lean forward slightly and use your hand to scoop all of your breast tissue from your underarm area into the cup. This ensures that the entire breast is encased in the cup. Often, women who think a cup is too big realize it fits perfectly once they position their tissue correctly.

Understanding Bra Anatomy

  • The Band: This is the foundation. It should be snug enough to stay parallel to the floor without riding up your back.
  • The Cups: These contain the breast tissue. There should be no "quad-boob" (overflowing tissue) or gaping at the top.
  • The Underwire: If your bra has wires, they should sit on your ribs, circling the breast tissue, never sitting on it.
  • The Straps: They are there for stability, not heavy lifting. You should be able to slide two fingers under them comfortably.

International Sizing: Decoding the Labels

Shopping online opens up a world of lingerie brands, but sizing standards vary wildly. A US 'DDD' is a UK 'E', while an EU 'E' is different entirely. Our converter tool handles these complexities.

  • US/CA: Uses standard inch measurements. Cup progression: D, DD, DDD, G.
  • UK: Known for a wider range of cup sizes. Cup progression: D, DD, E, F, FF, G, GG.
  • EU (Europe): Uses centimeters for band size (e.g., 70, 75, 80). Cup sizes are generally standard but skip double letters like DD.
  • FR (France): Band sizes are different math entirely (EU Band + 15).

Common Bra Styles Explained

Knowing your size is step one; knowing your style is step two.

  • T-Shirt Bra: Seamless, molded cups designed to be invisible under tight clothing.
  • Balconette: A lower cut bra that lifts from the bottom, creating a shelf-like appearance. Great for lower necklines.
  • Plunge: Features a very low center gore, perfect for deep V-neck tops.
  • Bralette: Unstructured, wire-free comfort, usually sized S-M-L rather than band/cup.
  • Sports Bra: Designed to minimize bounce. "Compression" styles flatten, while "Encapsulation" styles separate and support.

Frequently Asked Questions (FAQ)

Q: How often should I measure my bra size?

It is recommended to measure yourself at least once every six months, or after any significant weight change, pregnancy, or hormonal shift. Breast tissue density and shape change over time, affecting fit even if the scale hasn't moved much.

Q: What is a "Sister Size"?

Sister sizes are bra sizes that have the exact same cup volume but different band lengths. For example, a 34C has the same cup volume as a 32D and a 36B. If a 34C fits well in the cup but the band is too loose, you would size down to the sister size of 32D. Our calculator automatically provides these alternatives.

Q: Why does one brand fit differently than another?

Just like jeans, bra sizing varies by manufacturer. Some brands run firm in the band, while others are stretchier. Shape also plays a role; a brand known for shallow cups won't fit a projected breast shape well, even in the correct "size." Always check the specific brand's size chart when possible.

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

The most tell-tale sign is the band riding up your back. The band should sit horizontally across your back. If it arches upward, it's too loose to provide support. Another test is the finger test: you shouldn't be able to pull the band more than an inch or two away from your back.