NBA teams will have to start measuring the exact height of players this season, ending a yearslong practice of players fudging inches for vanity or gamesmanship.

The league's 30 clubs recently received a directive from NBA offices ordering team physicians to take precise player height measurements during training camp, league sources confirmed to NBC News on Friday.

Players must be barefoot or wearing nothing more than socks on their feet when measured. The same directive also instructs teams to look at the driver's licenses or passports of all players to confirm their dates of birth.

The story was originally reported Thursday night by The New York Times.

“A consistent process has been created to ensure the integrity and accuracy of the data on team rosters,” NBA spokesman Mike Bass told the paper.

The practice of reporting player heights an inch or two off has been around for nearly as long as the game has existed.

Recently retired Dallas Mavericks icon Dirk Nowitzki took a playful swipe at his former teammate, José Juan "J.J." Barea Mora, who is generously listed as 6 feet tall.

Nowitzki retweeted the Times story while tagging Barea, "you ok?"

Players and teams generally want to inflate height to make cagers taller. For example, NBA legend Charles Barkley is officially listed at 6 feet, 6 inches, but longtime fans have long believed "the Round Mound of Rebound" is closer to 6 feet, 4 inches tall.

But in some cases, players want to be seen as shorter, most notably two-time NBA Finals MVP Kevin Durant.

While Durant, who just left the Golden State Warriors for the Brooklyn Nets, is officially listed at 6 feet, 9 inches tall, basketball aficionados are convinced he's almost 7 feet tall.

Early in his career, Durant feared that coaches would pigeonhole him in roles traditionally suited for big men if they believed him to be 7 feet tall. Durant has proven to be one of the league's most capable long-range shooters, a skill not traditionally associated with tall players.

“For me, when I’m talking to women, I’m 7 feet. In basketball circles, I’m 6-9," he told The Wall Street Journal in 2016.

"But really, I’ve always thought it was cool to say I’m a 6-9 small forward. Really, that’s the prototypical size for a small forward. Anything taller than that and they’ll start saying, ‘Ah, he’s a power forward.’ ”

Boogie joked that he told KD to stop standing next to him. Boogie listed at 6-11, Durant at 6-9. pic.twitter.com/E2OIJwXKVS — Adam Zagoria (@AdamZagoria) June 29, 2016

And Durant's former Golden State teammate DeMarcus "Boogie" Cousins, listed as 6 feet, 11 inches tall, has even joked about it.

“I keep telling him to stop standing by me, man,” Cousins told SNY.tv just ahead of the 2016 summer Olympics. “I think people are starting to figure out, I might be about 6-7. He’s every bit of 7 feet, every bit.”