Overall Diameter
mm & inches
Speedometer Error
% correction
Ground Clearance
ride height change
Rim Fitment
compatibility check
Enter Your Tire Sizes
Fill in both sizes or paste a tire code like 225/45R17
Current Tires
Enter rim width to check fitment
New Tires
Enter rim width to check fitment
Found the Right Size? Pick a Rim Style.
Once you know the numbers, preview different wheel designs on your actual car with AI. Upload a photo and see how each style fits your ride.
15+ wheel styles · Works on any car · AI-powered
See the Difference on a Real Car
Different tire sizes change your car's stance, ground clearance, and overall look. Here's what a wheel and tire swap looks like with AI.
Stock Setup
New Tire & Rim SetupWhat Is a Tire Size Calculator?
A tire size calculator compares two tire sizes and shows you the exact differences in diameter, sidewall height, circumference, revolutions per mile, speedometer accuracy, and ground clearance. Every tire has three key numbers: the section width in millimeters, the aspect ratio (sidewall height as a percentage of width), and the rim diameter in inches. Changing any of these numbers affects how your car drives, handles, and reads speed.
This tool uses standard tire industry formulas to calculate every metric instantly. No guessing, no approximation - just the math that tire engineers use.
Preview New Tires on Your Car
Found the right tire size? Upload your car photo and see the new setup on your actual vehicle - AI-generated in seconds.
15+ rim styles · AI-powered fitment
Also on Android & iOS
Preview tire and wheel changes on the go with the free mobile app.
Frequently Asked Questions
How does the tire size calculator work?
Enter your current and new tire sizes (width, aspect ratio, and rim diameter) and the calculator instantly computes diameter difference, sidewall height change, speedometer error, ground clearance change, and revolutions per mile. All math uses standard tire industry formulas.
Will changing tire size affect my speedometer?
Yes. Larger tires cause your speedometer to read slow (you're going faster than displayed), while smaller tires cause it to read fast. The calculator shows the exact percentage error and a corrected speed table for 30, 45, 60, 70, 80, and 100 mph.
How do I know if a tire fits my rim?
Enter your rim width in inches in the optional field. The calculator checks whether the tire width falls within the recommended range for your rim (typically 70-95% of the tire's section width in inches).
What is aspect ratio on a tire?
The aspect ratio is the sidewall height expressed as a percentage of the tire's section width. For example, a 225/45R17 tire has a sidewall that is 45% of 225mm = 101.25mm tall. Lower aspect ratios mean shorter, sportier sidewalls.
Can I see how new tires look on my car before buying?
Yes - Car Editor's AI wheel and tire preview lets you upload a photo of your actual car and see any wheel and tire combination applied to it in seconds. You'll see the exact stance, profile, and fitment before you commit to buying.
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