Bra Size Converter
Calculate an estimated bra size (band + cup) in EU, UK and US from two simple measurements. The calculation runs entirely in your browser — no measurement is sent anywhere.
How it works
A bra size is made up of two pieces of information: a band (the underbust measurement, in centimeters or an even number of inches) and a cup (a letter that depends on the difference between the bust and underbust measurements). This tool applies the most common conversion formulas to estimate both values from your measurements and display them in the EU, UK and US sizing systems.
How do I measure correctly?
Measure your underbust just below your bust, keeping the tape measure horizontal and snug but not tight. Then measure your bust at its fullest point while breathing normally, wearing a non-padded bra or no bra. The more accurate these two measurements are, the more reliable the calculated result will be.
Why can results differ from brand to brand?
There is no single official conversion formula: manufacturers use slightly different sizing patterns and band calculation methods (the "+4" method used here, the newer "direct" method, etc.), which can shift the result by one band size. Treat this result as a reliable starting point and always try several nearby sizes when buying from a new brand for the first time.
Your measurements stay strictly local: no calculation is sent to a server — everything happens in your browser.