How to Measure Your Bra Size: Step-by-Step Guide

How to Measure Your Bra Size at Home

Finding the right bra size starts with two simple measurements:
your under-bust and your bust.

All you need is a soft tape measure and a mirror. For best results, measure without a bra or in a lightly lined, non-padded bra.

Before you start

• Stand up straight

• Keep your arms down by your sides

• Hold the tape measure horizontal and close to the body

• Don’t pull the tape too tight — but don’t let it sag either

Step 1: Measure your under-bust

This measurement determines your band size.

• Place the tape measure directly underneath your bust

• Hold it snugly and straight around your body

• Make sure the centimetre side is facing you

• The tape should sit close to the skin (not loose)

💡 Why snug matters:
Bras are made with elastic, but tape measures are not — so holding the tape close to your body gives the most accurate result.

👉 Round your measurement up or down to the nearest 5 cm.

Under-bust measurement → Band size

Step 2: Measure your bust

This measurement helps determine your cup size.

• Place the tape measure loosely over the fullest part of your bust

• Keep it horizontal across the chest and back

• Ensure the tape is sitting at the same height all the way around

• The centimetre side should face outward

Step 3: Calculate your cup size

Your cup size is worked out by calculating the difference between your bust measurement and your under-bust measurement.

Bust difference → Cup size

Putting it together

Once you have:

• Your band size (from the under-bust measurement), and

• Your cup size (from the difference),

you’ll have your starting bra size.

✨ Example:
If your under-bust measures 80 cm and your bust measures 99 cm, the difference is 19 cm, which equals a D cup.
Your size would be 14D.

Next step: check the fit

Measuring gives you a great starting point, but numbers alone don’t tell the whole story. How a bra feels and sits on your body matters just as much.

👉 Read our Good Fit vs Bad Fit guide to learn how to spot common fit issues — and what to do if something doesn’t feel quite right.

Measuring at home is a great starting point, but every body is different, and bra styles, brands, and shapes can affect fit.

If your bra feels uncomfortable, digs in, gaps, or needs constant adjusting, a professional fitting can help fine-tune your size and style for the best support and comfort.