Where to find your rim size right now

Your rim size is printed on the sidewall of your tire, stamped on the inside of your wheel, and listed in your vehicle's owner manual. The fastest method is to look at the tire itself — walk around your car and read the numbers on the black rubber wall. You will see a sequence like "225/65R17" or "205/55R16". The last two digits are your rim size: that 17 or 16 is the diameter in inches.

If you cannot read the tire clearly or prefer a second source, open your driver's side door and look at the placard glued to the inside edge of the door frame. This label lists the manufacturer's recommended tire and rim size. Your owner manual has the same information in the tire and wheel section, usually near the front or back of the book.

The rim size you find will be the diameter only — the width and offset (how far the wheel sits from the hub) are separate measurements you may need later, but the diameter is what most people mean when they ask "what size rim do I have."

Key Takeaways

  • Your rim diameter is the last two digits on your tire's sidewall, measured in inches (like 16, 17, or 18).
  • The door jamb placard and owner manual both list your vehicle's factory rim size and are faster than measuring.
  • Rim size stays the same whether you replace one wheel or all four — the diameter does not change with tire wear.
  • If you are buying new wheels, confirm the diameter matches your current rim size unless you are intentionally upgrading.

Reading the tire sidewall correctly

Stand next to your tire and look for the raised or printed numbers running along the black rubber. You will see a code that starts with three digits (the tire width in millimeters), followed by a slash, then two more digits (the aspect ratio). After that comes the letter R (for radial construction), and then the rim size.

In the example "225/65R17", the 17 is your rim diameter in inches. In "205/55R16", the 16 is your rim size. This number is always the last part of the sequence before any other markings. Write it down or take a photo so you have it when you shop for replacement wheels or tires.

All four tires on your vehicle should show the same rim size, even if the tire width or aspect ratio differs between front and rear. If they do not match, you have mixed rim sizes on your car, which is unusual and worth checking against your owner manual.

Using the door jamb placard

Open your driver's side door fully and look at the inside edge of the door frame where it meets the body of the car. You will see a white or silver label, usually about the size of a credit card, glued to this area. This is the Tire and Loading Information placard, and it lists the vehicle manufacturer's recommended tire size and rim diameter.

The placard shows the size in the same format you see on the tire: "225/65R17" or similar. The last two digits are the rim size. This placard is the official specification for your vehicle, so if it differs from what you read on your tire, the placard is correct — your tire may be an aftermarket replacement that does not match the factory spec.

Some vehicles have the placard on the fuel door or inside the trunk lid instead of the door jamb. If you cannot find it on the driver's door, check these other locations or consult your owner manual for the exact placement.

Checking your owner manual

Your vehicle's owner manual contains a tire and wheel section, usually in the maintenance or specifications chapter. This section lists the factory rim size, the recommended tire size, and often includes a diagram showing how to read tire sidewall markings.

The manual is the most reliable source because it reflects what the manufacturer installed on your vehicle when it left the factory. If you have lost your physical manual, you can read a PDF version from the manufacturer's website by entering your vehicle's year, make, and model. Many dealerships also provide digital copies if you ask.

What rim size means and why it matters

Rim size is the diameter of the wheel measured in inches from one edge to the opposite edge, passing through the center. A 17-inch rim is 17 inches across. This measurement is fixed — it does not change based on tire wear, inflation, or how much weight the vehicle carries.

Rim size matters because tires must match the rim they are mounted on. A tire designed for a 17-inch rim will not fit properly on a 16-inch rim, and forcing it can damage both the tire and the wheel. When you replace tires or wheels, you need to know your rim size to order the correct parts.

Rim size is separate from rim width (how wide the wheel is) and offset (how far the wheel extends from the hub). You may need these measurements if you are upgrading to custom wheels, but for routine tire replacement, the diameter alone is usually what you need.

Common rim sizes and what they look like

Most passenger vehicles use rim sizes between 14 and 20 inches. Smaller cars often have 14, 15, or 16-inch rims. Mid-size sedans and crossovers typically use 17 or 18-inch rims. Larger trucks and performance vehicles may have 18, 19, or 20-inch rims. Luxury and sports cars sometimes go larger, up to 22 inches or more.

The rim size is always a whole number — you will never see 17.5 or 18.3. If you see a decimal in the tire code, it is part of the width or aspect ratio, not the rim size. The diameter is always the last number in the sequence, after the R.

If you are unsure whether you read the number correctly, compare it to what the door placard says. They should match. If they do not, you may have an aftermarket tire that does not match your vehicle's factory specification, which is worth investigating before your next tire purchase.

What to do if you cannot find the information

If your tires are too worn to read clearly and you cannot access the door placard or manual, call your vehicle's dealership with your vehicle identification number (VIN). The dealership can look up your factory rim size in their system and tell you over the phone. This takes a few minutes and costs nothing.

You can also visit a tire shop and ask them to check your rim size. They can measure the wheel or read it from the tire if any part of the sidewall is still legible. Most shops will do this for free, especially if you are considering buying tires from them.

As a last resort, you can measure the rim yourself with a tape measure, but this is less accurate than reading the printed specification. Measure from the inside edge of the rim on one side to the inside edge on the opposite side, passing through the center. Round to the nearest whole number — that is your rim diameter.

Frequently Asked Questions

Is rim size the same as wheel size?

Rim size refers to the diameter only. Wheel size includes the rim diameter plus the width and offset. When someone asks "what size wheels do you have," they usually mean the diameter, but technically wheel size is more specific. For tire replacement, the rim diameter is what matters.

Can I put a different rim size on my car?

You can install a different rim size, but your tires must match the new rim diameter. If you go from 17-inch to 18-inch rims, you need 18-inch tires. Changing rim size affects your speedometer accuracy and fuel economy slightly. Check your owner manual or a tire professional before making this change.

Do all four wheels have to be the same rim size?

Yes, all four wheels on a standard passenger vehicle should be the same rim diameter. Some performance vehicles have different sizes front and rear, but this is rare and is specified in the owner manual. If your four wheels do not match, investigate why before driving.

What if the tire sidewall and door placard show different rim sizes?

The door placard shows the factory specification. If your tire shows a different size, you have an aftermarket tire that does not match the original equipment. This is not necessarily a problem, but confirm with a tire professional that the tire is safe for your vehicle before driving.

Do I need to know rim width and offset to replace my tires?

For tire replacement only, you need the diameter. Width and offset matter if you are buying new wheels or upgrading to custom rims. Your tire shop can help you determine whether you need these measurements based on what you are replacing.