Bra Size Calculator

Estimate bra band and cup size from underbust and bust measurements.

—Estimated size
—Band
—Cup

Measurements should be snug but not tight. Sizing varies between brands and countries — treat this as a starting estimate and try styles on where you can.

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How to use Bra Size Calculator

Three quick steps — no sign-up needed

  1. Step 1

    Choose inches or centimetres

    Select the unit that matches your measuring tape.

  2. Step 2

    Measure band and bust

    Band is the underbust measurement; bust is at the fullest point. Keep the tape level and breathe normally.

  3. Step 3

    See band and cup estimate

    Read the suggested band and cup combination, then try brands on - sizing is not universal.

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About Bra Size Calculator

Bra Size Calculator estimates band and cup size from underbust (band) and fullest-bust measurements. Shoppers search "bra size calculator", "calculate cup size", and "band size from underbust" when labels differ between brands or countries.

Pick Inches or Centimetres, enter band and bust, and get a starting size. Real-world fit still depends on shape, stretch, and brand sizing charts - always use the estimate as a try-on guide, not a guarantee.

Measure over a lightly lined or unlined bra you already own, or bare as preferred for consistency. Re-measure after weight change, training changes, or pregnancy-related shifts.

This is a fit aid, not clinical advice. If you have pain, implants, or post-surgery needs, consider a professional fitter or clinician.

Benefits of Bra Size Calculator

Inches or cm Work in the units on your tape without converting first.
Band and cup together See a combined size estimate from two simple measurements.
Brand try-on starting point Narrow the range before you order or visit a store.
Private calculation Measure at home and calculate online without an app install.

Frequently asked questions

How do I measure for bra size?

Measure underbust for band and the fullest point of the bust for cup, tape level, then enter both values here.

Why do brands feel different in the same size?

Sizing systems and cuts vary. Use the calculator as a starting point and adjust by fit.

Can I use centimetres?

Yes - switch the units control to Centimetres.

What if I am between sizes?

Try both neighbouring sizes and prioritise band support and cup containment over the label alone.

Is this medical advice?

No - it is a consumer sizing estimate for everyday fit.