Bra Size Calculator
Enter underbust and full bust measurements to get a quick estimated size and a helpful starting point for shopping.
Bra Size Finder
Your estimated size is:
Note: Sizes vary by brand. Use this as a starting point.
Find your estimated bra size online
This bra size calculator is built to give a quick starting point using two measurements: underbust and full bust. Many people search for terms like measure bra size, find my bra size, or bra size calculator usa because sizing can vary by brand and style. A calculator does not replace a fitting room, but it can reduce guesswork and help narrow down the most likely band and cup size.
The page works best when measurements are taken carefully with a soft measuring tape. Measure the underbust snugly around the ribcage and the full bust at the fullest point. From there, the tool estimates a band size and then uses the difference between bust and band to suggest the cup size.
How bra sizing works
- Band size is based on the ribcage measurement.
- Cup size is based on the difference between the bust and the band.
- Brand fit, fabric stretch, and style can still change the final fit.
Why this calculator is useful
A quick online calculator is helpful before shopping, ordering from a new brand, or checking whether your current size still makes sense. It is especially useful if you want a starting point before trying multiple sizes manually.