Bra Size Calculator
Last updated: June 2026 · Free · No sign-up required
Enter values above and click Calculate to see your result instantly.
Quick reference
Cup size by bust-minus-band difference:
| Difference | Cup |
|---|---|
| 1 inch | A |
| 2 inches | B |
| 3 inches | C |
| 4 inches | D |
| 5 inches | DD/E |
apps Small jobs, done in one click
Everyday calculators are the workshop drawer of the site — quick utilities for the moments when you need a number now and a phone calculator won't cut it. Age, date difference, GPA, fuel cost, time-to-decimal, password strength — pick a tool and you're one click from your answer.
speed Loads in under a second
Every tool is plain HTML + JavaScript with the calculation logic compiled in. No spinner, no "verifying browser" splash, no five-second wait while ads load. Hit the page, fill the form, get the answer. Slow tools waste your time and ours.
devices Works on every device
Responsive design tested down to a 320px-wide phone screen. The input fields use native number/date keyboards on iOS and Android, the calculate button is thumb-sized, and the result still reads big and bold on the smallest screen. No app to download, ever.
sentiment_satisfied No funny business
No newsletter pop-ups, no "create an account to see the answer", no fake countdown, no fake stock counter, no upsell. Two ad slots per page (clearly labelled as Advertisement) keep the site free — that's the whole business model.
Interpretation guide
Bra fit basics:
| Concept | Detail |
|---|---|
| Band | Measure snugly under the bust |
| Bust | Measure around the fullest point |
| Cup | From bust minus band difference |
| Sister sizes | Same cup volume, different band |
Formula & methodology
Formula: Cup size = round(bust) - round(band) in inches; each inch of difference is one cup
Bra size combines a band number and a cup letter. Measure the band snugly under the bust and the bust around its fullest point; the difference in inches sets the cup (1 inch = A, 2 = B, and so on). The calculator returns your US size and sister sizes — equivalent cup volumes at adjacent band sizes — which help when a band feels too tight or loose. Sizing varies by brand, so treat it as a starting point.