How to read a tire size

Every tire has its size printed on the side, in a code like 265/70R17 112T. Here is what each part means.

Part	Means
P or LT (if shown)	P is a passenger tire. LT is a light truck tire, built for heavier loads and towing. No letter usually means a passenger tire made to European standards.
265	Width in millimeters, from one sidewall to the other: about 10.4 inches.
70	Aspect ratio: the sidewall is 70% as tall as the tire is wide, about 7.3 inches.
R	Radial construction, used on almost every tire today.
17	The wheel (rim) size it fits, in inches.
112T	Load index (112 = 2,469 lb per tire) and speed rating (T = up to 118 mph).

How tall is my tire?

Add the wheel size to two sidewalls. For 265/70R17: 17 + 2 × 7.3 = 31.6 inches tall. Try your own size:

Tire size

31.6 in tall

Truck sizes like 33x12.50R15

Off-road and lifted trucks often use flotation sizes, which give the height in inches directly. A 33x12.50R15 tire is 33 inches tall, 12.5 inches wide, and fits a 15-inch wheel.

Where to find your size

Look on the side of the tire, or on the sticker inside the driver's door frame. The door sticker shows the size your vehicle came with, which is the best starting point if the tires on it now might not be stock.

Compare it with a bigger size

Common questions

What does the R mean on a tire?

R means radial construction, which almost every car and truck tire uses today. You may also see ZR on high-speed tires, or a dash or D on older bias-ply and some trailer tires.

What is the difference between P and LT tires?

P (passenger) tires are built for cars, SUVs and light trucks in everyday use. LT (light truck) tires have stronger construction and carry heavier loads at higher pressures, for towing and hauling. Stay with LT if your vehicle came with LT tires.

What do 33x12.50R15 tires mean?

That is a flotation size, used for off-road and lifted trucks. The first number is the overall height in inches (33), the second is the width in inches (12.50), and the last is the wheel size (15). The calculator reads these sizes too.

What are load index and speed rating?

The number and letter after the size, such as 112T, are the load index (how much weight each tire can carry) and the speed rating (its maximum safe speed). When changing sizes, keep at least the load index and speed rating your vehicle calls for.