You need one thing: a soft measuring tape. The kind used for sewing. If you don't have one, use a long piece of string and then measure it against a ruler. That's it. No special equipment. No fitting room. No awkwardness. Just you, two measurements, and the knowledge you need to shop with confidence.

This is the same method we use at our professional fitting events — and it takes about 5 minutes.

Before You Start

For the most accurate results:

  • Wear a non-padded bra, or none at all
  • Stand up straight — relaxed, not holding breath
  • Use a mirror if measuring yourself, or ask someone you trust to help
  • Measure in centimetres (cm) — SA sizes use centimetres

The Two Measurements You Need

1
Your Band Measurement (Under-Bust)
Wrap the tape firmly (not tight) around your body, directly underneath your bust — just where your bra band sits. Keep the tape parallel to the floor. Breathe normally and measure at the end of a normal exhale.
Write down this number in cm. This is your under-bust measurement.
2
Your Cup Measurement (Over-Bust)
Wrap the tape loosely around the fullest part of your bust — usually across the nipple line. Keep the tape parallel to the floor. The tape should be snug but not pressing in. Don't hold your breath.
Write down this number in cm. This is your over-bust measurement.
3
Calculate the Difference
Subtract your under-bust measurement from your over-bust measurement. This difference (in cm) tells you your cup size.
Example: Under-bust = 82cm, Over-bust = 96cm → Difference = 14cm → Cup size = DD

Your Band Size (South Africa / UK Standard)

Under-Bust (cm)SA / UK Band Size
63 – 67 cm30
68 – 72 cm32
73 – 77 cm34
78 – 82 cm36
83 – 87 cm38
88 – 92 cm40
93 – 97 cm42
98 – 102 cm44
103 – 107 cm46

Your Cup Size (Difference in cm)

Difference (cm)Cup Size
10 cmA
11 – 12 cmB
13 – 14 cmC
15 – 16 cmD
17 – 18 cmDD
19 – 20 cmE
21 – 22 cmF
23 – 24 cmFF
25 – 26 cmG
27 – 28 cmGG
29 – 30 cmH
31 – 32 cmHH
33 – 34 cmJ
35 – 36 cmJJ
37+ cmK

Example: Under-bust = 82cm → Band size 36. Over-bust = 99cm. Difference = 17cm → Cup size DD. Your size: 36DD.

Understanding Sister Sizes

If your calculated size doesn't feel quite right when you try it on, sister sizing can help. Sister sizes have the same cup volume but different band sizes:

  • Go up a band size and down a cup letter: 36DD → 38D (same volume)
  • Go down a band size and up a cup letter: 36DD → 34E (same volume)

Use sister sizing when: the band fits but cups are slightly wrong, or cups fit but band is slightly off.

What If My Number Seems "Too Big"?

Many women are surprised by their cup size. A 38G sounds large, but it simply means you have a 38-inch band and your bust is 7 inches larger. That's it. There is no "too big" when it comes to what's correct for your body.

The measurement doesn't lie. Your body is not the problem. Whatever number comes out — that's your size, and beautiful bras exist in that size, just for you.

A Final Note on Measurements vs. Fit

Measuring gives you a starting point — not a definitive answer. Every bra brand has slight differences. Breast shape matters too. That's why we always recommend trying different styles and sizes in the same measurement zone.

When in doubt, chat with us. That's what we're here for. No bra should feel like a compromise.