Forget law school. Send your kids to comedy camp if you want them to support you in your old age.

“Seinfeld” might be the show about nothing, but it’s also made an incredible $2.7 billion — with a “b” — since it went off the air 12 years ago, according to Time Warner, which owns the series.

That makes “Seinfeld” the most profitable 30 minutes in TV history.

It is rare that TV studios reveal the amounts made by their most successful TV series, but at an investors’ conference late last month, execs spilled the beans about just what a moneymaker the show has been over the past 12 years.

Jerry Seinfeld and co-creator Larry David have an undisclosed ownership stake in the show that has paid them in the hundreds of millions for the reruns of the show.

Details of the huge sums were buried in a report of the conference carried by the trade magazine The Hollywood Reporter. The main idea of the conference was for Time Warner to brag to potential investors how well the company is doing.

The numbers indicate that reruns on regular TV have grossed $2.3 billion since 1998.

Revenues from cable were about $380 million, execs reported.

“Seinfeld” made 180 episodes during its nine-year run — which means that each half-hour episode has earned more than $14 million so far.

That does not include what the show — or its stars — made while the show was on NBC in its original run.

For years, Forbes magazine has been estimating that Jerry makes between $65-80 million a year from reruns of the show.

But the startling size of the show’s total earnings was never known before.

But if any show deserved to make billions, say the experts, it was probably “Seinfeld.”

“The thing about ‘Seinfeld’ is that it was well-written, well-acted and well-produced — a triple threat,” said Marc Berman, “Mr. Television” of Mediaweek.

“People related to the characters and it’s just plain funny. This is a show that can last forever. It’s like watching ‘I Love Lucy,’ it’s still funny and you can keep laughing at it today.”

But Jerry likely won’t be master of this domain forever.

Pop culture professor Robert Thompson predicts “Seinfeld” will someday be toppled by “The Simpsons.”

“When the end of world history comes, ‘The Simpsons’ will be the most-rerun show of all time and make the most money,” said Thompson, founding director of the Bleier Center for Television and Popular Culture at Syracuse University.

Apparently, other cast members from the show are not sharing in the billions.

Co-stars Jason Alexander, Michael Richards and Julia Louis-Dreyfus have a portion of the revenues from sales of “Seinfeld” DVDs — something they held out for in contract negotiations for the series’ final season. But not the show’s syndication money.