About this tool

Real Bra Size Calculator turns two measurements into a bra size, showing the working and a drawing of what that size typically looks like from the side and above, so the letters finally mean something. It skips the outdated “add 4 inches” rule that puts many people in the wrong band. You also get sister sizes, a fit check for a bra you already own, side-by-side size comparisons, an estimated breast weight, and sizing across seven countries. Free to use, no sign-up, nothing to sell.