Bra Size Calculator
Calculate bra band and cup size from underbust and bust measurements in inches.
Sister sizes share the same cup volume — when you go up one band size, go down one cup size (and vice versa). A professional fitting is recommended for the most accurate results, as fit can vary between brands and styles.
What is Bra Size Calculator?
The Bra Size Calculator determines your band and cup size from two simple body measurements taken in inches — underbust and bust circumference.
Accurate bra sizing improves comfort and support. This tool uses the standard sizing method where band is derived from the underbust measurement and cup size from the difference between bust and band.
How does the Bra Size Calculator work?
The underbust measurement determines the band size. It is rounded to the nearest whole number and then adjusted to the nearest even number.
The difference between the bust measurement and the calculated band size determines the cup letter, from AA (0 or less) through I+ (8 or more).
How to use the Bra Size Calculator?
- Measure your underbust directly under the bust and enter the value in inches.
- Measure the bust at its fullest point and enter the value in inches.
- The calculator automatically determines the band size, cup size, and full bra size.
- Try on sizes near the result, as fit can vary between brands and styles.
Example
Try the calculator with your own numbers
- Enter your values in the input fields above.
- Adjust the values to match your situation.
- The result updates instantly as you change the inputs.
Benefits of using the Bra Size Calculator
- Instantly calculates both band and cup size from two basic measurements.
- Uses a clear lookup table covering sizes from AA through I+.
- A helpful starting point before a professional fitting, saving time and improving confidence.
Who should use the Bra Size Calculator?
- Students and professionals who need fast, accurate results.
- Anyone who wants to verify a manual calculation.
- People who prefer a quick answer over working it out by hand.
Tips for getting the most out of the Bra Size Calculator
- Double-check the values you enter before relying on the result.
- Use the calculator to verify manual calculations or estimates.
- Bookmark the page if you use it regularly.
Frequently Asked Questions
What are sister sizes?
Sister sizes share the same cup volume. Going up one band size and down one cup size (or vice versa) gives a comparable fit. This is useful when your exact size is unavailable.
Should I round up or down when measuring?
Measure snugly without compressing the skin. The calculator rounds the underbust to the nearest even number automatically, so enter your exact measurement.
Does this work for all body types?
This tool provides a standard sizing estimate. For the most accurate fit, especially if you have significant size differences or are between sizes, a professional bra fitting is recommended.
This calculator gives you fast, reliable answers whenever you need them. Try it now and keep it handy for future calculations.
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