The quickest way to find your rim size

Your rim size is stamped directly on the wheel itself, usually on the inner edge where it faces the brake. Look for a series of numbers that includes a diameter (like 17 or 18) and a width (like 7.5 or 8). The format is typically something like "17x7.5" — the first number is diameter in inches, the second is width in inches. You do not need any tools; you just need to crouch down and look at the inside of one of your wheels.

If the stamping is worn or hard to read, your vehicle's door jamb label or owner's manual will list the original rim size. The door jamb label is usually on the driver's side door frame, near where the door latches, and includes tire and wheel information. If you have aftermarket rims (wheels you bought separately and installed), the original label may not match what you have now — in that case, the physical stamping on the wheel is your true measurement.

Key Takeaways

  • Rim size is stamped on the inner edge of the wheel itself, showing diameter and width in inches (for example, 17x7.5).
  • Your vehicle's door jamb label, usually on the driver's side door frame, lists the factory rim size if the wheel stamping is unreadable.
  • The owner's manual contains the original rim specifications and can confirm what size came on your vehicle from the factory.
  • If you have aftermarket rims, the physical stamping on the wheel is more accurate than any factory label, since you may have replaced them.

Reading the numbers on your wheel

Rim size always includes two main measurements. The first number is the diameter — how wide the wheel is from edge to edge, measured in inches. Common diameters are 15, 16, 17, 18, 19, and 20 inches. The second number is the width, also in inches, and tells you how thick the wheel is from front to back. A width of 7 inches is narrower than 8.5 inches.

You may also see an offset number, which looks like "ET45" or "+35" — this describes how far the wheel sits out from the hub and does not change the rim size itself. Ignore it for the purpose of identifying your rim size. The two numbers you need are the diameter and width, and they will be clearly separated by an "x" or a period.

Where to look on the wheel

Start by looking at the inside surface of the wheel — the side that faces the brake and suspension. This is where manufacturers stamp the size information. You may need to turn the steering wheel all the way to one side to see the inside of the front wheels clearly. For rear wheels, you can usually see the inside edge by crouching behind the car.

The stamping is often small and may be partially obscured by dirt or brake dust. Use a flashlight and wipe the area with a dry cloth if needed. If the stamping is completely worn away or illegible, move on to checking your door jamb label or owner's manual instead of guessing.

Using your door jamb label

Open your driver's side door and look at the frame where the door latches — this is the door jamb. You should see a white or yellow label with vehicle information. This label lists tire size, recommended tire pressure, and wheel size. The wheel size will be listed as a diameter and width, matching the format you would see stamped on the wheel.

Keep in mind that this label shows the factory rim size — the size that came on your vehicle when it was new. If you have replaced your wheels with aftermarket rims, the label will not reflect your current setup. In that case, trust the stamping on the wheel itself.

Checking your owner's manual

Your owner's manual contains a specifications section that lists wheel and tire information. Look for a section titled "Specifications," "Wheels and Tires," or "Technical Specifications." The manual will show the factory rim size in the same format as the door jamb label — diameter by width in inches.

The owner's manual is useful if your door jamb label is missing or damaged, or if you want to confirm what size rims your vehicle originally came with. You can find digital copies of most owner's manuals online by searching your vehicle's year, make, and model plus "owner's manual PDF."

What to do if you have aftermarket rims

Aftermarket rims are wheels you purchased separately and had installed, rather than the factory wheels that came with your car. If you have these, the door jamb label and owner's manual will show the original size, not your current size. The only reliable source is the stamping on the wheel itself.

If you bought the rims from a shop or dealer, you can also contact them with your vehicle information and ask what size they installed. Some shops keep records, especially if the work was done recently. If you no longer have that information, the wheel stamping is your best option.

Why knowing your rim size matters

Knowing your rim size helps you buy the correct tires, order replacement wheels, or check whether new wheels will fit your vehicle. Tires must match your rim diameter — a tire for a 17-inch wheel will not fit a 16-inch rim. The width also matters for tire fitment, though there is some flexibility there.

If you are shopping for new wheels or tires and you are unsure of your size, having the correct measurement prevents ordering the wrong part and wasting time and money on returns. It also helps you communicate clearly with tire shops or mechanics when you need work done.

Frequently Asked Questions

Can I tell my rim size just by looking at my tire?

No. Tire size and rim size are different measurements. A tire size like "225/45R17" tells you the tire width, aspect ratio, and rim diameter, but it does not tell you the rim width. You must look at the wheel itself to find the complete rim size.

What if the numbers on my wheel are hard to read?

Clean the area with a dry cloth and use a flashlight to see the stamping more clearly. If it is still illegible, check your door jamb label or owner's manual for the factory size. If you have aftermarket wheels and cannot read the stamping, contact the shop where they were installed if you have that information.

Does rim size affect how my car drives?

Yes. Larger rims can change your car's handling, fuel economy, and ride comfort. Rims that are too wide for your vehicle can rub against the suspension or body. Always match the rim size to what your vehicle was designed for, or consult a tire professional before going significantly larger or smaller.

Are rim size and wheel size the same thing?

Yes, the terms are used interchangeably. The rim is the metal part of the wheel that the tire mounts onto. When someone asks your wheel size or rim size, they are asking for the same measurement: diameter and width in inches.