How to measure bra size in inches with a soft tape
Measure loose, snug and tight underbust around the same level ribcage line. Then measure the fullest bust circumference while standing, leaning forward 90 degrees and lying down. Keep the tape parallel without compressing breast tissue.
Enter every number in inches. A soft tape is easiest to position, but a non-stretch string can be marked and checked against a rigid ruler when needed.
How this six-measurement bra size calculator estimates band and cup
The snug underbust establishes the nearest even UK band. The loose and tight measurements help identify whether a nearby sister size may be more comfortable or more supportive.
For the cup estimate, the calculator uses leaning bust when the standing-to-leaning difference is 2.5 inches or less. With a larger difference it averages all three bust measurements. The AMAB profile uses a weighted average of standing, lying and leaning measurements.
How to read an A Bra That Fits calculator starting size
A result such as 28F/FF UK is a range of adjacent cup sizes on the same band. Begin with the calculated size, then compare one cup up, one cup down or the suggested sister size when the band feels clearly too firm or too loose.
Check the band independently by trying the bra backwards and upside down. A new band should feel firm on the loosest hook without painful pressure. After fastening normally, scoop and swoop all tissue into the cups before judging cup fit.
Bra size calculator in inches questions and answers
How accurate is the A Bra That Fits calculator?
It is designed to give a strong starting size from six measurements. It cannot account for every breast shape, bra construction, brand grading choice or comfort preference, so nearby sizes should still be tried when possible.
Why does this bra size calculator use six measurements?
Three underbust measurements show ribcage size and compressibility. Standing, leaning and lying bust measurements capture tissue that can distribute differently in one upright measurement.
Should I use the bra size calculator in inches or centimeters?
Use the unit shown most clearly on your tape. The calculator normalizes centimeters and inches before applying the same method, so either entry mode can produce the same physical starting size.
What does a result such as 28F/FF mean?
It means both adjacent cup sizes are reasonable starting points in the selected sizing system. Cup letters are tied to band size, so 28F does not have the same cup volume as 34F.
Why is my calculated bra size different from the size I wear?
Many size charts add four inches to the underbust or fit into a limited product range. This method starts closer to the measured ribcage and may return a smaller band with a larger cup letter.
Does the calculator store my body measurements?
No. Calculation happens in the browser. The site does not submit or save the six measurements as a calculation history.