Ben 10 heights can be inconsistent so from now on I'll use this for a reference. Everyone's height is scaled from Vilgax, who's 12 feet.
Alien Force[]
Ben[]
1.723 meters
5 ft 7.8 inches
Gwen[]
1.723 meters
5 ft 7.8 inches
Kevin[]
1.873 meters
6 feet 1.7 inches
Max[]
1.95 meters
6 feet 4.7 inches
Alan[]
1.674 meters
5 feet 5.9 inches
Swampfire[]
2.676 meters
8 feet 9.35 inches
Echo Echo[]
0.666 meters
2 feet 2.22 inches
Humungousaur[]
4.194 meters
13 feet 9.1 inches
Jetray[]
1.93 meters
6 feet 3.98 inches
Big Chill[]
2.08 meters
6 feet 9.89 inches
Chromastone[]
2.4 meters
7 feet 10.49 inches
Brainstorm[]
1.3 meters
4 feet 3.18 inches
Spidermonkey[]
1.1 meters
3 feet 7.3 inches
Goop[]
2.174 meters
7 feet 1.59 inches
Alien X[]
2.65 meters
8 feet 8.33 inches
Cannonbolt[]
1.95 meters
6 feet 4.7 inches
Upchuck[]
0.566 meters
1 foot 10.29 inches
Diamondhead[]
2.096 meters
6 feet 10.5 inches
Lodestar[]
1.852 meters
6 feet 0.9 inches
Rath![]
1.933 meters
6 feet 4.1 inches
Forever Knight[]
1.979 meters
6 feet 5.9 inches
Vulkanus[]
3.244 meters
10 feet 7.7 inches
Vilgax[]
3.6576 meters
12 feet
DNAlien[]
1.999 meters
6 feet 6.7 inches
Highbreed[]
3.95 meters
12 feet 11.5 inches
Classic series[]
Ben (Kid)[]
1.22 m
4 feet
Gwen (Kid)[]
1.31 m
4 feet 3.75 inches
Max[]
1.95 meters
6 feet 4.7 inches
Heatblast[]
1.93 meters
6 feet 3.98 inches
Wildmutt[]
1.4 meters
4 feet 7.19 inches
Diamondhead (Classic)[]
1.9 meters
6 feet 2.8 inches
XLR8[]
1.49 meters
4 feet 10.66 inches
Grey Matter[]
0.253 meters
9.96 inches
Four Arms[]
2.7 meters
8 feet 10.3 inches
He's stated to be 12 feet but has only appeared that tall in his debut. For the rest of the series he's constantly shown to be shorter than 12 feet.
Stinkfly[]
1.429 meters
4 feet 8.26 inches
Ripjaws[]
2.176 meters
7 feet 1.67 inches
Upgrade[]
1.97 meters
6 feet 5.56 inches
Ghostfreak[]
1.97 meters
6 feet 5.56 inches
Cannonbolt (Classic)[]
1.89 meters
6 feet 2.4 inches
Wildvine[]
1.9534 meters
6 feet 4.9 inches
Blitzwolfer[]
2.274 meters
7 feet 5.3 inches
Snare-Oh[]
2.539 meters
8 feet 3.96 inches
Frankenstrike[]
2.59 meters
8 feet 5.97 inches
Upchuck (Classic)[]
0.826 meters
2 feet 8.5 inches
Lmao he shrank
Ditto[]
1.1 meters
3 feet 7.3 inches
Eye Guy[]
2.03 meters
6 feet 7.9 inches
Way Big[]
55.815 meters
183 feet
Animo[]
1.665 meters
5 feet 5.55 inches