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Bra Size Chart & Calculator

Calculate your perfect bra size instantly and convert between US, UK, and EU measurements.

How to measure underbust

1. Underbust

Measure snugly around your ribcage, directly under your bust.

in
How to measure overbust

2. Overbust

Measure loosely around the fullest part of your chest.

in
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How to Find Your Bra Size

Wearing the right bra size is essential for comfort, support, and posture. Astoundingly, studies suggest that up to 80% of women wear the incorrect bra size. By utilizing an accurate women's bra size chart and calculator, you can eliminate the guesswork from lingerie shopping.

Our interactive calculator simplifies the process. All you need is a soft measuring tape and two measurements: your underbust and your overbust. The tool will automatically calculate your exact US, UK, and European (EU) bra sizes using standard sizing algorithms.

How to Measure Bra Size Chart

To find your band size (the number part of your size, like the '32' in a 32 bra size chart), you must measure your underbust.

  • Wear an unlined, non-padded bra.
  • Wrap a measuring tape snugly around your ribcage, directly beneath your bust.
  • Ensure the tape is level all the way around your back.
  • Exhale slightly and note the measurement in inches. If it's an odd number, standard US/UK sizing usually rounds up to the nearest even number.

How to Measure Bra Cup Size Chart

Your cup size (the letter part of your size) represents the volume of your breasts relative to your band size. This is calculated using your overbust measurement.

  • Wrap the measuring tape somewhat loosely around the fullest part of your chest (usually across the nipples).
  • Keep the tape parallel to the floor.
  • Subtract your calculated band size from this overbust measurement.
  • The difference in inches dictates your cup letter.

Standard Cup Bra Size Chart Reference

If you prefer to calculate it manually, here is the standard mathematical difference used to determine US and UK cup sizes:

Difference (Inches) US Cup Size UK Cup Size
0 - 1 inchAA
2 inchesBB
3 inchesCC
4 inchesDD
5 inchesDD / EDD
6 inchesDDD / FE
7 inchesGF

Note: Sizing standards can vary slightly by manufacturer. This bra size calculator provides the most widely accepted standard metric.

Frequently Asked Questions

You need two measurements: your underbust (ribcage directly under your breasts) to find your band size, and your overbust (the fullest part of your chest). The difference between these two measurements determines your cup size.
Subtract your band size from your overbust measurement. A 1-inch difference is an A cup, 2 inches is a B cup, 3 inches is a C cup, and 4 inches is a D cup. Our bra size chart with pictures above illustrates this visually.
A sister size maintains the same cup volume but changes the band size. For example, if you measure a 32D, your sister sizes are 34C (larger band, smaller cup letter) or 30DD (smaller band, larger cup letter). If a 32 feels too tight, you would go to a 34 band but drop down a cup size.
It is recommended to measure your bra size every 6 months, or whenever you experience significant weight changes, pregnancy, or start a new fitness routine, as your breast tissue and ribcage size can change.
Gaping cups usually indicate that the cup size is too large, or that the specific bra style does not suit your breast shape. Try going down a cup size or switching to a demi or balconette style.
Your band should fit snugly but comfortably on the loosest hook when new. If it digs into your skin painfully, rides up your back, or restricts your breathing, the band size is likely too small.
US and UK sizes are identical for cup sizes A through D. However, after D, they diverge. For example, a US DDD is equivalent to a UK E cup, and a US G is a UK F. Always check a conversion chart when buying international brands.

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