Primary Fit Guide
To measure yourself for your perfect fit it is best to use a soft tape measure. If you do not have one, you can use twine. Follow the instructions below, and afterwards, just measure the twine with a ruler.
Your overbust is the measurement around the fullest part of your breasts
Your underbust is the measurement directly underneath your breasts. You may need to lift your breast tissue up to take a clean reading.
Your waist is the narrowest part of your torso.
Your hips are measured around the largest part of your bottom
Looking for Shapewear fit guides?
Shapewear plays by its own rules. Adhesive bras, bodysuits, low-rise undergarments - they all come with their own sizing guide.
You’ll find the right guide for the specific piece on the product page.
Fit
Bralettes
If you are shopping in XS-XL sizes, follow the chart below to find your best size. Use a typical top size and typical cup size.
| A | B | C | D | DD/E | F | |
|---|---|---|---|---|---|---|
| 8 | XS | XS | S | S | S | M |
| 10 | XS | XS/S | S | S/M | M | M/L |
| 12 | S | S/M | M | M/L | L | L/XL |
| 14 | M | M | M/L | L/XL | XL | - |
| 16 | M | L | L/XL | XL | - | - |
Bras
| AU Size | A | B | C | D | E | F | G | |
|---|---|---|---|---|---|---|---|---|
| 8 | Overbust (cm) | 77-79 | 79-81 | 81-83 | 83-85 | 85-87 | 87-89 | 89-91 |
| Underbust (cm) | 65-70 | |||||||
| 10 | Overbust | 82-84 | 84-86 | 86-88 | 88-90 | 90-92 | 92 -94 | 94-96 |
| Underbust | 71-76 | |||||||
| 12 | Overbust | 87-89 | 89-91 | 91-93 | 93-95 | 95-97 | 97-99 | 99-101 |
| Underbust | 77-82 | |||||||
| 14 | Overbust | 92-94 | 94-96 | 96-98 | 98-100cm | 100-102 | 102-104 | 104-106 |
| Underbust | 83-88 | |||||||
| 16 | Overbust | 97-99 | 99-101 | 101-103 | 103-105 | 105-107 | 107-109 | 109-111 |
| Underbust | 89-94 | |||||||
Briefs and Thongs
| Size | Waist (cm) | Hips (cm) |
| XS | 55-63 | 82-88 |
| S | 63-69 | 88-94 |
| M | 69-76 | 94-101 |
| L | 76-33 | 101-109 |
| XL | 33-84 | 109-114 |
| XXL | 84-99cm | 114-122cm |
A few Primary pointers
Most of your bra or bralette's support comes from the band. Not the straps. Not magic. Just a good, firm hug around your underbust is right.
When trying a new bra, start on the loosest hook. You want it snug, not squeezing the life out of you. Two fingers under the band = just right.
If you’re doing it up on the tightest hook straight away, the band’s too big. Think of it like jeans - you don’t buy them already stretched out.
If it’s digging in on the loosest hook, it’s too small. You deserve support, not bruises.
All elastic softens over time. That’s why a good bra gives you room to adjust the band.
A well-fitting band = comfort, lift, and a bra that actually does its job. Get that part right, and the rest just falls into place.
Book a Virtual Fitting
At Primary we offer virtual fittings to make sure your purchase is the right fit.
Choose either a Find Your Fit before your purchase or a Check Your Fit after delivery to ensure you are wearing the right size.