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Free Bra Size Calculator

Find your bra size from underbust and bust measurements, with US/UK/EU conversion and sister sizes.

Works offline once loaded
inches

Snug, directly under the bust.

inches

Around the fullest point, relaxed.

inches

Lean over so the bust hangs free, then measure the fullest point.

Band method

Enter your underbust and bust measurements to see your size.

πŸ“ How to measure

  1. Underbust: stand relaxed, wrap the tape level and snug around your ribcage right under the bust and exhale.
  2. Bust, standing: wrap the tape level around the fullest part of the bust, snug but not squeezing.
  3. Bust, leaning (optional): bend forward 90 degrees and measure the fullest part again to see your range.

Measure braless or in a non-padded bra, with the tape level and snug but not tight. Exhale normally for the underbust.

⚠️ Sizing varies a lot between brands and styles β€” use this as a starting point and always check the brand's own fit guide.

πŸ”’ Measurements are processed in your browser β€” nothing is uploaded.

Common uses

  • Find Your Bra SizeTwo measurements, one answer.
  • US/UK/EU ConversionConvert your size between regions.
  • Sister SizesSame cup volume, different band.
  • Measure at HomeGet accurate measurements yourself.
  • Re-Fit After ChangesRe-check your size after body changes.
  • Online Shopping SizeOrder the right size first time.

How It Works

Measure your underbust and bust, and get an estimated bra size in US, UK and EU sizing, plus your sister sizes β€” the same cup volume on a tighter or looser band. With clear measuring instructions. Everything stays on your device.

  1. 1
    Measure underbust
    Snug and level, directly under the bust.
  2. 2
    Measure bust
    Around the fullest point, tape relaxed.
  3. 3
    Read your sizes
    US, UK and EU sizing side by side.
  4. 4
    Try sister sizes
    If the fit is close but not right, try the listed sister sizes.

Measurements are processed in your browser β€” nothing is uploaded.

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Frequently Asked Questions