How old is SpongeBob?

How old is SpongeBob? I don't mean how old is the series, I mean what is SpongeBob's age if he were a real person. I ask because his age seems to be ambiguous in the show.

He has a full-time job
He has his own house
He is always referred to as a kid (especially in the movie)
He acts childish and immature
In one episode, he was pretending to be an adult/grown-up

character spongebob-squarepants

Best Answer

Well, SpongeBob has a date of birth: July 14, 1986. If we assume that the series takes place in our times, that would make him 28.

However, Bart and Lisa Simpson have been 8 and 10 for more than 20 years now. So if we assume that his age is constant in the show (which premiered in July 17, 1999), that would make him 13.

Is that data useful in this cartoon? Not really. We don't really know what rules fictional underwater realms play by, and to further confuse matters, I'm not even sure how relatively old SpongeBob is because, according to Wiki, the lifespan of a sea sponge varies greatly:

Sponges in temperate regions live for at most a few years, but some tropical species and perhaps some deep-ocean ones may live for 200 years or more.

However, it appears that the show's creator has kept SpongeBob's age vague on purpose:

Although SpongeBob's driver's license says his birthdate is July 14, 1986, Hillenburg joked that he is fifty in "sponge years". He explained that SpongeBob actually has no specific age, but that he is old enough to be on his own and still be going to boating school.