To read a tire size, look at the sidewall. The tire code usually looks something like this: P215/60R16.
"P" stands for passenger tire;
"215" is the tire width in millimeters;
"60" is the aspect ratio, the height compared to the width;
"R" means it's a radial tire; and
"16" is the rim diameter in inches.
So, in this example, it's a passenger tire that's 215 millimeters wide with a height of 60% of the width, meant for a 16-inch rim. Read more