The 24-hour format reading for 00:00 is "zero hundred" or formally "zero hundred hours." However, this is primarily used in military, aviation, or technical contexts. In everyday American and British English, people almost always use the 12-hour clock. For 00:00 in daily conversation, everyone would simply say "midnight." You can also say "twelve AM." The word "tonight" provides perfect context if you say something like, "The party tonight starts at twelve."

Read as mid-night

Hey Sasha, I hope you are doing well. Common ways to say 00:00 are: 1. “midnight” (informal, everyday English) 2. “zero hundred hours” (military/official) 3. “zero zero hundred hours” (more formal military) In my business English classes, I ask my students to use the second option, whenever they're having a formal conversation.

I just usually say "midnight."