UNDONE BY INTIMATES

The Size & Fit Guide

The perfect fit begins with understanding your body. Explore our lingerie size conversions, measurement guides and fit advice to discover your most confident fit.

01 / Bra sizing

Find your bra size

Begin by measuring around your ribcage, directly below your bust. Keep the tape level and comfortably snug, then use the table to find your approximate band size.

International band conversion

AU/NZEUUK/USUnderbust
8653063–67 cm
10703268–72 cm
12753473–77 cm
14803678–82 cm
16853883–87 cm
18904088–92 cm
20954293–97 cm
221004498–102 cm
Band conversions are a general guide. Sizing can vary between styles and brands, so use your measurements alongside each product’s fit notes.

How to measure

STEP 01

Measure your underbust

Wrap a soft tape measure around your ribcage, just beneath your bust. Keep it level and note the measurement in centimetres.

STEP 02

Measure your bust

Measure around the fullest part of your bust without pulling the tape tight. Keep the tape parallel to the floor.

STEP 03

Compare measurements

Use your underbust measurement to estimate your band size. Cup sizing varies by band and label, so check the style-specific guidance too.

STEP 04

Check the fit

Your band should feel secure on its loosest hook, sit level across your back, and support without digging in.

A well-fitting cup should contain the bust without gaping or spilling. Straps should stay in place without carrying the full weight of the support.

02 / Brief sizing

Find your brief size

Measure around the fullest part of your hips, keeping the tape level. If you fall between sizes, consider your preferred coverage and the fabric’s stretch.

AU/NZInternationalHip measurement
8XS84–89 cm
10S90–95 cm
12M96–101 cm
14L102–107 cm
16XL108–113 cm
182XL114–119 cm
203XL120–125 cm
Fit and measurements can differ by design. Please refer to the individual product page for style-specific sizing and fabric information.
03 / Fit notes

A few fit reminders

  • Measure over bare skin or a light, unpadded bra for the most consistent result.
  • Keep the measuring tape level, close to the body, and comfortably snug—not tight.
  • Measurements are a starting point. Your comfort and the fit of the specific style matter most.
  • If you are between sizes or need a hand choosing, contact us and include the style you are considering.