His birthdate is July 14, 1980. My knowledge: SpongeBob is 10 in Kamp Koral. Pearl is 1. In S4E11, it is Pearl's 16th birthday. Therefore, 10+(16-1)=25. In Sleepy Time, we get a glimpse of his birthday, which according to the fake drivers licence, is July 14, 1986. I believe the day and month are correct, but because it's in a dream, it might be slightly inaccurate.
Edit: A video came out a while before this that I didn't see, and it states https://www.youtube.com/watch?v=SY9GIl0opys. This evidence causes a bunch of inconsistencies, because with the evidence of this video SpongeBob is 31. But with my evidence, SpongeBob is 25. This, honestly, is probably a moment when SpongeBob's creators were not thinking
