Silly spelling question

[raweater]

I have a silly spelling question for the recipe book I'm writing, when does "cup" take an s?

Such as:
1/2 cup (quite sure there's no s)
1 cup (obviously no s)
1 1/2 cup (not sure)
2 cups (obviosuly an s)

Thanks to anyone who can clear this up for me.

[sport]

I think that anything more than one has an S so one and a half has an S

[juliebove]

Or you could just use the abbreviation of c. and then you wouldn't have to worry about the "s".

[raweater]

I'm in Canada and may be giving/selling it to some people who's first language is french, where c stands for tea/tablespoon and t for cup, I wouldn't want someone to put 1 teaspoon of walnuts with 1 cup of salt! Although it would probably be obvious lol.

[ArcturusXIV]

Anything over 1 cup requires an "s". Whoever posted that earlier is correct. So 1 1/2 Cup"s" is with an "s".