There are different shower sizes, and there are several factors that you have to consider before getting one set up. The ideal size would be if you can swing your elbows without getting near or touching the walls. A comfortable size would be 4 x 5 ft. For two people, 5 x 5 or 6 x 4 will be sufficient. A 3 x 4 may be too small for some two individuals.
Unless you are going to install other accessories, the measurements mentioned above will be enough. A shower that is too big will just end up wasting space. Showers without doors are also an option.
In a 4 x 5 area, this feature can make it seem more spacious. A 3.5 x 5.1 area is good enough for two individuals. But if you want to add a bench, the length or width has to be increased.
There are many other shower sizes that can be used. A 36” x 36” size will be fine for a single individual (provided they are of average height). For couples, 40” x 60” is ideal.
Master bath dimensions differ, but 7’9” x 11’4” is not uncommon. In this case, the shower can measure 5′ x 3’6”. The double vanity can be 8’ long. An 8 ft vanity can also fit in an 8.5 x 10.5 bathroom easily.
Using these same dimensions, a 4 x 4 shower can be installed. An extra foot will be required if a bench is going to be installed. These dimensions are sufficient to keep water from splashing out of the shower. In these setups, the toilet can be placed in different locations.
The average door size is between 20 to 36 inches widthwise. There are also glass shops that sell doors measuring 26 to 32 inches. The increments are at two inches.
The minimum acceptable size is 30 x 30 inches. The 36 x 36 dimensions are the so-called roll-in showers. These dimensions are big enough for people to get on a wheelchair. But it is better if the dimensions are bigger. But you should also avoid making it larger than necessary.
In the end, the ideal shower size is something only you can decide. Take into account the number of people who are going to shower and what amenities will be included. If you want the bathroom with all the trimmings –benches, shelves, etc- make it at least 6 x 6 ft.