Finding your size can feel confusing—especially when calculators and charts don’t tell the full story. 

That’s why we believe the best bra is the one that feels right on you, not just what the label says.

DEBUNKING TRADITIONAL BAND AND CUP MEASURING BASICS


Traditionally, your cup size is the difference between the Overbust (fullest part of your bust) minus Underbust (ribcage)

To get your band size, if your underbust measures 67–71cm, you are a 70 band / 32 band (+4 inches method) or even be 28 band in some online calculators. 

To get your cup size, every 1 inch difference between your overbust and underbust refers to 1 cup size. Eg 1 inch = A cup, 2 inches = B cup, 3 inches = C cup

📌 Kate’s note:
“This means that although my measurements say I’m a 28C (77cm/71cm), in real life I fit best in a 32A. It’s not that calculators are wrong — it’s that bras in the market don’t translate directly to the math. The ‘C’ I get on a calculator is not the actual C-cup volume available in stores, which results in me wearing bras that are often too tight on the band and gaping in the cups."

THE REALITY CHECK

Petite frames often find that bands feel too tight and cups gape, even when the calculator says otherwise.

Full-bust women may discover the opposite — that the cups are too small or the band rides up, despite being "the right size."

This is why knowing your measurements is key, so you can find the best fit according to individual brands' fit guide. Next, trying them on and noticing how they feel on your body is just as important as what the numbers say.

OUR APPROACH AT PERK BY KATE

- We prioritize comfort over strict measurements

- We look at how the band and cups sit on you, not just numbers

- We fit-test our designs on petite and fuller bust frames of different measurements to figure out the best sizing fit. We found that the best 

- Cup coverage takes reference to the traditional A, B, C cup coverage, but determined by Full, Plus, Curvy namings, so we focus on how it fits on you, instead of letting a number determine your fit. 

OUR CUP MEASUREMENT GUIDE

Here's how to measure for yourself.

- Take your underbust (pink dotted line) and overbust (red dotted line) measurements 

 

 

PBK Size International Sizing Underbust (cm) Overbust (cm)
XS 30A, 30B 63 - 67 70 - 77
S 32A, 32B 68 - 72 75 - 82
S(Full) 32C 68 - 72 82 - 85
S(Plus) 32D 68 - 72 85 - 88
S(Curvy) 32DD/32E 68 - 72 88 - 91
M 34A, 34B 73 - 77 80 - 87
M(Full) 34C 73 - 77 87 - 90
M(Plus) 34D 73 - 77 90 - 93
M(Curvy) 34DD/E 73 - 77 93 - 96
L 36A, 36B 78 - 82 85 - 92
L(Full) 36C 78 - 82 92 - 95
L(Plus) 36D 78 - 82 95 - 98
L(Curvy) 36E 78 - 82 98 - 101
XL 38B 83 - 87 90 - 97
XL(Full) 38C 83 - 87 97 - 100
XXL 40B 88 - 92 95 - 102
3XL/CURVY 42B, 42C 93 - 97 100 - 107

UNDERWEAR SIZING GUIDE

All our lingerie come in US sizes, in the following measurements and conversion chart:
   SIZE
S
M
L
XL
XXL
   US SIZE
0-2
2-4
4-6
8-10
12-14
   UK SIZE
6
8
10
12
14
    ASIAN SIZE
   (FOR PANTIES
   ONLY)
S
M
L
XL
XXL
   BUST
30-31"
32-34"
34-36"
36-38"
38-40"
   WAIST
23-25"
25-27"
27-28"
28-30"
30-32"
   HIP
32-34"
34 - 37.5"
37.5-38.5"
38.5-41"
41-42.5"

HOW DO I TAKE CARE OF MY BRALETTES?

We always recommend caring for your lingerie the traditional way — a gentle handwash in cold water, followed by laying flat to dry. It’s the best way to keep delicate fabrics looking and feeling their finest.

That said, we understand life gets busy. Every Perk by Kate bra has been tested to withstand over 50 washes in the machine, as long as it’s on a delicate cycle (low spin, low temperature, max 30 minutes). Each of our sample has been test worn for over a year before launching. Just remember to hook your bras and place them in a laundry bag before washing.

For coloured lace styles, if you’re unsure about colourfastness, we suggest a quick test on a discreet area before washing.