LeBron James has dunks that look almost too easy for a player his size. But the number I want is the height of his best jump, not the force of his best poster. With his head about two to three inches above the rim in the highest clips I use, I put his vertical at roughly 41 to 43 inches.
Start with the rim
The NBA currently lists LeBron at six-foot-nine. In the source video, I use six-foot-eight-and-a-half without shoes and allow roughly an inch for shoes, giving me a working on-court height of six-foot-nine-and-a-half. At that height, he would need to jump about 38-and-a-half inches for the top of his head to meet a ten-foot rim. In his best-looking NBA jumps, he appears another two or three inches above that. That puts the calculation around 41-and-a-half, and I leave a little room on either side for the camera angle and height assumption.
The useful clips are the ones where his head and the rim are visible together near the top of the jump. A hard finish through traffic can hide the takeoff or peak, even if the play is more impressive. LeBron is also tall enough that a head position above the rim does not automatically imply a 45-inch jump: on the video’s height assumption, rim level takes only about 38½ inches. The extra two or three inches we can see are what bring the estimate into the low 40s.
What I would not claim
The six-foot-nine-and-a-half working height is an assumption, and a video angle can move the apparent head-to-rim gap. If his actual height in those shoes were half an inch different, the calculation would shift by half an inch. That is why the TikTok gives a range rather than an official-sounding 41.5. It also means a claimed 40-plus vertical should be checked against the actual jump, not accepted or rejected solely because LeBron is such a powerful dunker.
The source video also covers Gerald Green, Derrick Rose and Amen Thompson. Their numbers are in the NBA vertical table. The games versus warmups article is useful here too, because even an incredible in-game dunk may not be a player's highest jump.