33-inch tires
A 33-inch tire is about 33 inches tall. In metric, the closest sizes are 285/75R16 (32.8 in), 275/75R17 (33.2 in), 295/65R18 (33.1 in), 275/60R20 (33.0 in).
"33s" is shorthand for any tire close to 33 inches tall. Inch sizes say it outright; metric sizes get there from width and sidewall, so each rim size has its own set. The bars below are drawn to the same scale, so you can see which ones really are 33 inches.
33x inch sizes
Metric sizes about 33 inches tall
24-inch rims
33-inch tire questions
What size is a 33-inch tire in metric?
It depends on the rim. On a 16-inch rim, 285/75R16 is 32.8 inches tall. On a 17-inch rim, 275/75R17 is 33.2 inches tall. On an 18-inch rim, 295/65R18 is 33.1 inches tall. On a 20-inch rim, 275/60R20 is 33.0 inches tall.
Is a 33x12.50 the same as a metric 33?
Not quite. 33x10.50R15 is a true 33 inches tall and 10.5 inches wide, while metric "33s" range from 32.5 to 33.5 inches and are usually narrower.
Will 33-inch tires change my speedometer?
Yes, if they are taller or shorter than the size you have now. Going from a 31.6-inch 265/70R17 to a 33-inch tire changes the reading by about 4.4%. Put your own size into the tire size calculator to see the exact change.