How to Measure Your Bra Size at Home

What you need

A soft fabric measuring tape (the kind tailors use), a mirror, and a non-padded bra or bralette. Wear nothing too thick — the measurement should be against your skin or a thin bra.

Step 1 — Measure your under-bust

Wrap the tape directly under your bust, where the band of a bra would sit. Pull it firmly snug — not tight enough to squeeze, but with no slack. Keep the tape parallel to the floor all the way around. Round to the nearest whole inch (or centimetre).

Step 2 — Measure your bust

Wrap the tape around the fullest part of your bust, usually across the nipple line. Keep it loose — do not compress the tissue. Stand normally and breathe out. Round to the nearest whole inch.

Step 3 — Calculate your band

Modern method: round your under-bust to the nearest even number. That is your band. Skip the old "+4 inches" method — it gives bands that are several inches too loose for most people.

Step 4 — Calculate your cup

Subtract your under-bust from your bust. The difference equals your cup letter:

1 inch = A cup
2 inches = B cup
3 inches = C cup
4 inches = D cup
5 inches = DD cup
6 inches = DDD (or E in UK)
7 inches = G (or F in UK)

Frequently Asked Questions

Should I measure with a bra on?

Either works. Without a bra is more accurate for the under-bust. With a thin, non-padded bra is more accurate for the bust because it gives some shape.

Why should I skip the +4 method?

The +4 method came from the 1930s when bra fabric had no stretch. Modern stretchy bands fit best at your true under-bust measurement.

How often should I re-measure?

Every 6 months, after weight change, after pregnancy, and after starting hormonal birth control or hormone therapy.

📏 How to Measure Your Bra Size at Home