Bra, Underwear & Sleepwear Size Guide
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Eco Intimates bras use Australian sizing as a guide. Most customers get the best fit by starting with the size they usually wear, then using the guide below to check that their current bra size is fitting correctly.
If you’re unsure of your size, use your underbust measurement to choose your band size, then select your cup range.
Our wire-free bras are designed to comfortably contain and support your bust from under the arm towards the centre. Because of this fuller cup coverage, you may find that a larger cup range fits better than expected—particularly if your bust spills over the top or sides of your current bra.
1) Band Size Guide
Measure firmly around your ribcage directly beneath your bust. Use this measurement to find your recommended Eco Intimates band size.
Our bras are designed with a firm-fitting underband to give your bust the best support. If you prefer a softer, less-firm fit, choose one band size larger.
| Under-bust | Eco Size | AU | EU | US/UK | Underbust (in) |
|---|---|---|---|---|---|
| 65–70 cm | XS | 8 | 65 | 30 | 25.6–27.6 |
| 71–76 cm | S | 10 | 70 | 32 | 28.0–29.9 |
| 77–82 cm | M | 12 | 75 | 34 | 30.3–32.3 |
| 83–89 cm | L | 14 | 80 | 36 | 32.7–35.0 |
| 90–95 cm | XL | 16 | 85 | 38 | 35.4–37.4 |
| 96–102 cm | 2XL | 18 | 90 | 40 | 37.8–40.2 |
2) Choose Your Cup Range
Option 1: Use your current bra size
Use the cup size from your best-fitting bra:
- A, B or C cup → A–C
- D, DD or E cup → D–E
- F or G cup → F–G
Check your fit: If your bust spills over the top or sides of your current bra, the cup may be too small. Choose the next cup range where available.
Tip: Going up a band size also adds some cup room, but a band that is too loose will provide less support. If your band fits comfortably, keep the same band size and move up a cup range instead.
Option 2: Use Your Measurements
Measure around the fullest part of your bust, then subtract your underbust measurement.
| Bust minus underbust | Approximate cup size | Choose |
|---|---|---|
| 12–17 cm | A–C cup | A–C |
| 18–23 cm | D–E cup | D–E |
| 24–28 cm | F–G cup | F–G |
These measurements are a guide. If your measurement falls near the next range or you prefer fuller coverage, choose the larger cup range where available.
3) Underwear Size Guide
Our underwear ranges from XS (AU/UK 6–8) to 2XL (AU/UK 16–18), with approximately 4.8 cm added between each size.
Start with the underwear size you usually wear. If you are unsure of your size, measure around the fullest part of your hips and bottom, keeping the tape level. If your lower tummy is fuller than your hips, measure around that area as well and use the larger measurement.
If you prefer a softer fit, choose the larger size.
Ruffle Knickers: Choose your usual size for the intended cheeky fit through the bottom. Many customers prefer to size up for more coverage and a softer feel through the elastic.
| Eco Size | Low Hip | Low Hip (in) | AU/UK/NZ | US | EU |
|---|---|---|---|---|---|
| XS | 88–92 cm | 34.6–36.2 | 8 | 4 | 36 |
| S | 93–97 cm | 36.6–38.2 | 10 | 6 | 38 |
| M | 98–102 cm | 38.6–40.2 | 12 | 8 | 40 |
| L | 103–107 cm | 40.6–42.1 | 14 | 10 | 42 |
| XL | 108–112 cm | 42.5–44.1 | 16 | 12 | 44 |
| 2XL | 113–117 cm | 44.5–46.1 | 18 | 14 | 46 |
| 3XL | 118–122 cm | 46.5–48.0 | 20 | 16 | 48 |
4) Sleepwear & PJs Sizing
Sleepwear is designed for a relaxed fit. Choose your usual dress size unless the product page recommends otherwise.
| Eco Size | AU/NZ | US | UK | EU |
|---|---|---|---|---|
| XS | 8 | 4 | 8 | 36 |
| S | 10 | 6 | 10 | 38 |
| M | 12 | 8 | 12 | 40 |
| L | 14 | 10 | 14 | 42 |
| XL | 16 | 12 | 16 | 44 |
| 2XL | 18 | 14 | 18 | 46 |
5) Bandeau Sizing
The Bandeau is made with rows of shirring elastic and is designed around your usual dress size. If you have a fuller bust, choose the next size up for more room and coverage.
A bandeau that is too tight may flatten your bust rather than gently supporting it. Use the chart below to compare the garment measurements and available stretch with your full-bust measurement.
| Bandeau Size | Fits AU Sizes | Length | Laid Flat | Max Stretch | Max Around |
|---|---|---|---|---|---|
| XS/S | 8–10 | 20 cm | 27 cm | 45 cm | 90 cm |
| M/L | 12–14 | 21.5 cm | 29.5 cm | 55 cm | 110 cm |
| XL/2XL | 16–18 | 23 cm | 32 cm | 60 cm | 120 cm |
How to check: With a bra on measure around the fullest part of your bust. The approximate maximum circumference (Max around in the chart) is the furthest the bandeau stretches, so if your measurement is close to the maximum, choose the larger size where available.
Need Help?
If you’re unsure, I’m happy to help. Visit the Fitting Room for step-by-step personalised sizing advice.
