hosting a baby shower and would like to know how many cans of soda do i buy for approx. 40 people?!

I'd go for the 2 liter sized soda and have one or two that are d-caf. It's much cheaper and easier on the environment because you are recycling less. Have some ice and smaller cups and let people pour their own. Ladies don't drink as much as men, so for 40, with optional non carbonated drinks, 3 big bottles should be fine. Also, you might serve some sort of tea, hot or iced. It's super cheap to make and if it is herbal, the mom to be can drink it without worry. (Check the label for the pregnancy warning on the herbal tea box).

Provide water as well.

Mom of three and retired chef.

Buy them in the 2 liter size, it's much cheaper.
Buy 2 Sprites, 2 diet coke, 1 coke, 1 club soda as mixers.
buy 2 large bottles of Wood bridge Chardonnay and a 6 pack of lite beer
If it is a non alcoholic shower with no wine (no fun) then double the soda's, forget the club soda, and add 24 pack of bottled waters.

Professional party planner, 25 years.

Since you are also having punch, I would say 1 1/2 cans per person. Without the punch I would say 2 cans per person. Enjoy the shower.

you can assume 2 cans per person. plus a 10% buffer for a unexpected guests; you might have more than 40 guests.

Always good to assume a average or 2 sodas per person

80 cans