Maximum number of fixtures

I am adding a sink and shower to an existing bathroom. Is it acceptable to feed both from 1/2" copper or do I need to supply separate 1/2" copper feeds from 3/4" copper? If the former, what is the maximum number of fixtures permitted from 1/2" copper?

In my area it is 3 on 3.

At one time back in the 90's it was 2 hots and 3 colds on 1/2".

Check your local codes to see what code dictates in your area.

you can put a shower and a lav on 1/2, or a toilet and a lav in 1/2, but do not put a toilet and a shower in the same 1/2 supply.