I need help - if there is a pro bra fitter on here that would be perfect!

I have lost 4st5lbs and my bras are no good any more!

My underbust measurement is 40in - i pulled the tape tight and kept it level.
My fuller bust measurement is 46in - again I kept it level but did not pull too tight this time.

Can someone tell me why on some sites it tells me to add 4 inches, giving me a band size of 44, whereas other sites say that after 38in you round to the next even number so I would be 40 band size? Cup size I know is about the diff between the two and I am around an E depending on site and brand!

HELP NEEDED or just advice! Thank you! xxx

40DDD or 40F or Universal Cup Size 40D3

When in doubt, Ask Meta!
http://www.metafilter.com/116513/finding-the-right-bra-size-and-best-fit

I work in a lingerie store and I do bra fits almost everyday. When you measure your underbust is it exactly on 40 or you adding the 4 inches to get to 40? If you are exactly on 40, Katanthus is right. You'll be around a 40DDD. Be warned that there is no universal standard of making bras, so you might vary by a cup size depending on the brand.

Thank you, I am a 40 without adding the 4in so will look around the 40DDD mark - but I will get measured properly when I can xxx