You can do bra sizing on your own at home. Mostly because a lot of stores are trained in old (now irrelevant) methods and/or trained to also to just get you to buy a bra.



Your band size:

- It's your underbust measurement.

- If it's an odd number, you can round up or down depending on you prefer your fits.

-- However, if you're at 27 or below, you'll have to settle for a 28 band (you may have to sister size), because 26 bands and below are only custom-made.



Your cup size:

- Your BUST measurement minus your underbust measurement.



Example:

Underbust: 35" - Round up. 36"

Bust: 43"

Bra size: About a 36H, or 36G.



Hopefully this helps.

Also, bare in mind the bra style also counts for how they fit. The larger you are, you may need to opt for something more full-coverage.



EDIT: I forgot something important!!!!

When you do your bust measurement, you should also do a leaning measurement, where you're leaning forward. Your breasts will...fall away from your chest more?

When I do this, I do have about another inch or so on my bust measurement.

Try a 30E

Go to victorias secret and get a bra sizing but don't let them measure you with your bra on if your comfortable let them do it with your bra off or wear a loose tanktop with your bra off when they size you.