Do you have a bigger size?
'Più' — PYOO. One syllable. 'Grande' — GRAN-de.
Use when the item fits almost right but needs to be larger. Works for all clothing. If you need two sizes up: 'due taglie più grande'.
'Una taglia più grande' literally means 'one size bigger'. 'Più' here means more/bigger, not 'anymore'. 'Più grande' is the comparative of 'grande'. In Italian comparatives, 'più + adjective' is always used — there are no irregular comparatives except for migliore/peggiore.
Avete la taglia superiore?
Do you have the next size up?
Formal version.
Ce n'è una più larga?
Is there a wider one?
Specifically about width.
La quarantaquattro c'è?
Is the forty-four available?
Asks for a specific size directly.
When describing where a garment is tight, Italians point to the body part: 'qui alle spalle' (here at the shoulders), 'qui al petto' (here at the chest). This helps staff find exactly the right cut.