Although this question has been asked many times, only the questions or answers are very outdated.
I would like to host a Minecraft server with a few colleagues (with me 4 people). We would like to play a modpack with about 65-100 mods (like Attack of the B-Team). How much GB of RAM would I have to assign the server to start at all or how much GB should I add per player?
2.5 - 3 GB should be enough for 4 players.
From 100 mods I recommend depending on mods times at least 3GB, because it can come in the course of problems, especially if a lot is built, Chunkloader in the game, etc.
Yes, as the previous answers say I would min. 2-4 GB recommend.
I would take 3 to 5 GB. Speak from experience. This should give you little or no laggs or chunk errors