How to Read a Tire Sidewall Size Code

Every tire's sidewall carries a size code. Take P225/65R17 102H as an example:

Part	Meaning
P	Tire type: P = passenger, LT = light truck. No letter usually means a metric/Euro size.
225	Section width in millimeters, sidewall to sidewall.
65	Aspect ratio: sidewall height is 65% of the width.
R	Radial construction (almost all modern tires).
17	Fits a 17-inch wheel.
102	Load index: the maximum load the tire can carry at its maximum pressure (102 = 1,874 lb per tire).
H	Speed rating: H = up to 130 mph under test conditions.

Other markings

DOT code: the manufacturer, plant and the week/year made. See DOT date code.
UTQG: treadwear, traction (AA, A, B, C) and temperature (A, B, C) grades on passenger tires.
Max. load and max. inflation pressure: the tire's limits. This is not the pressure you should run. Use your door placard.
M+S / 3PMSF: mud-and-snow, or the three-peak mountain snowflake for severe snow. See tire types.

Replacement tires should match the size, load index and speed rating on your placard or owner's manual, or exceed them.

General information only, not a substitute for an in-person inspection by a qualified tire professional. If in doubt, have your tires checked.

Last updated October 28, 2026.