Bra Size Guide – How to Measure Your Bra Size at Home
Bra Size Guide – How to Measure Your Bra Size at Home
Finding the right bra size makes an enormous difference to comfort, posture, and how your clothes fit. Research suggests up to 80% of women are wearing the wrong bra size – often a band that’s too big and cups that are too small. Measuring yourself at home takes less than 5 minutes and can be done with a soft tape measure.
What You’ll Need
- A soft measuring tape
- A well-fitting (non-padded) bra, or no bra at all
- A mirror, or a friend to help
Step 1 – Measure Your Band Size (Underbust)
Wrap the tape measure firmly around your ribcage, directly under your bust. Keep it snug but not tight – you should be able to breathe comfortably. Round to the nearest whole number.
Australian Band Size Conversion
| Measurement (cm) | AU Band Size |
|---|---|
| 63–67cm | 10 |
| 68–72cm | 12 |
| 73–77cm | 14 |
| 78–82cm | 16 |
| 83–87cm | 18 |
| 88–92cm | 20 |
| 93–97cm | 22 |
| 98–102cm | 24 |
| 103–107cm | 26 |
Step 2 – Measure Your Bust (Fullest Point)
Measure around the fullest part of your bust, keeping the tape parallel to the floor. Don’t pull too tightly – the tape should sit smoothly without digging in.
Step 3 – Calculate Your Cup Size
Subtract your band measurement from your bust measurement. The difference tells you your cup size.
| Difference (cm) | Cup Size |
|---|---|
| Less than 1cm | AA |
| 1–2cm | A |
| 3–4cm | B |
| 5–6cm | C |
| 7–8cm | D |
| 9–10cm | DD |
| 11–12cm | E |
| 13–14cm | F |
| 15–16cm | FF |
| 17–18cm | G |
| 19–20cm | GG |
| 21–22cm | H |
| 23–24cm | HH |
| 25–26cm | J |
| 27–28cm | JJ |
| 29cm+ | K |
Example: Underbust 78cm (band 16) + bust 91cm = 13cm difference = F cup → Size 16F
How to Know If Your Bra Fits Correctly
The Band
- Should sit horizontally – not riding up at the back
- You should fit two fingers underneath, but no more
- Fasten on the loosest hook when new – tighten as the bra stretches
- The band provides 80% of support
The Cups
- All breast tissue should sit inside the cup with no spilling
- No wrinkling (cup too big) or quadra-boob (cup too small)
- Underwire should sit flat against ribcage, not on breast tissue
The Straps
- Comfortable – not digging in or slipping off
- Straps should not carry all the support – if they slip the band is too loose
The Centre Gore
- Should lie flat against your sternum
- If it lifts away, go up a cup size
Sister Sizes
Same cup volume, different band size. Try sister sizes when the cup fits but the band doesn’t:
- Looser band: go up a band, down a cup (e.g. 14D → 16C)
- Firmer band: go down a band, up a cup (e.g. 14D → 12DD)
Common Fitting Problems
| Problem | Cause | Solution |
|---|---|---|
| Band riding up | Band too big | Go down a band, up a cup |
| Straps digging in | Band too loose | Tighten band or go down a band size |
| Underwire poking | Cup too small | Go up a cup size |
| Cups wrinkling | Cup too large | Go down a cup size |
| Breast tissue spilling | Cup too small | Go up a cup size |
| Centre gore not flat | Cup too small | Go up a cup size |
Our Specialist Sizes
The Bra Shop Australia specialises in hard-to-find sizes including large cups (E through K), large backs (up to 36), small backs with large cups, mastectomy bras (10A–28E), and maternity & nursing bras (10B–20F).
Questions?
Our team has over 30 years of specialist fitting experience. Contact us at info@thebrashop.com.au for personal fitting advice.