The Student Room Group
focusing
Reply 2
focusing
Reply 3
They are both correct, I think, but I'm more used to using the former.
Focussing is the British English spelling, whereas focusing is the American way.
(Got this from dictionary.com)

"fo·cused or fo·cussed, fo·cus·ing or fo·cus·sing, fo·cus·es or fo·cus·ses "

Looks like it can be both.
Focusing is definitely used more, though.
Reply 6
nah, focussin forreal forreal
Focussing is how I spell it. It depends on where you are from, to be honest...
Reply 8
Dictionary.
Reply 9
Focusing.

Or if you're black you could use focussing in some form like this:

Blud he was fo' cussing ma shizzle bruv.
Either.
focusing.
look it up in the OED
It's either; personally I prefer focussing (and I think that's more commonly used in Britain). But I'm sure either would be fine :smile:
According to the Oxford Dictionary for Writers and Editors it is focusing
British people use focussing. If you spelt it