What size is the screen of the Galaxy S plus? I need to replace the sc

@helenmiles sounds like yo are contemplating a glass only repair. Take a look at this video and see if that is what you want to do. There is more than the cost of glass, you will a. have to make sure you remove the old one without destroying the display (not easy). b. You will have to make sure you have the right glue (OCA or LOCA) and then you have to make sure c. that you can adhere it back on the display without any air bubbles etc (definitely not easy) By the time you've added the cost for the tools and consumables, the cost will be fairly high as well. If you get it properly working. If you have never done a glass only repair, consider that there is a much easier option. Instead of trying to attach the glass only and hoping it will all work again, I'd recommend that you replace the complete display assembly. Here is a guide for the display replacment Remplacement de l'écran du Samsung Galaxy S9 Plus The display is available right here Galaxy S9+ Screen as well as many other places.

To answer your original question, the screen is a 6.2inch screen. The "kit" is available at places like this