Wear an unpadded bra or no bra
Measure your underbust snugly to find your band size
Round the underbust measurement to the nearest whole number
If using inches, add 4 if the number is even and 5 if the number is odd, or use your preferred sizing method
Measure around the fullest part of your bust
Keep the tape level and not too tight
Subtract the band size from the bust measurement
Use the difference to determine the cup size
Check a bra size chart for your band and cup combination
Try on bras in nearby sizes for the best fit
Adjust for different brand sizing if needed