Question
Does this guarantee the perfect bra size?
No. It gives a starting estimate. Real fit can vary by brand, style, wire shape, fabric stretch, and personal comfort preferences.
Daily utilities
Use OmniCalc's bra size calculator to estimate a starting band and cup size from bust and underbust measurements.
Bra size calculator
Use this to get a quick starting bra size from two measurements, then refine the fit based on comfort, support, and brand differences.
Measure around the fullest part of the bust and snugly around the ribcage under the bust. Treat the result as a starting point rather than a final answer.
Why this result matters
A measurement-based starting estimator that turns bust and underbust values into a practical band-and-cup size starting point with plain fit guidance. Use the tool above to enter a few clear inputs and get a practical answer you can use right away.
This bra size calculator uses bust and underbust measurements to estimate a starting bra size in a simple, readable way. It is helpful for first-pass size checks, online shopping prep, and comparing measurements across sizing systems, while still acknowledging that brand fit and style differences matter in real life.
Formula and method
The calculator converts measurements into inches, rounds the underbust to an even-number band size, then estimates the cup from the difference between bust and underbust measurements.
Example
If the bust is 36 inches and the underbust is 32 inches, the calculator estimates a starting size of 32D and adds practical fit notes about brand variation.
FAQ
Short answers to the questions people often ask before or after using the tool.
Question
No. It gives a starting estimate. Real fit can vary by brand, style, wire shape, fabric stretch, and personal comfort preferences.
Question
Those two measurements provide a practical starting point for estimating both the band size and the cup size.
Question
Try nearby sizes or sister sizes and adjust based on how the band, cups, straps, and support feel in actual wear.
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