Tire Size Calculator
Calculate tire dimensions and compare sizes from tire codes
Tire Size Calculator
Use the following calculators to find the dimensions of a tire based on its code. It can also provide a comparison of alternative tires that are compatible with a given wheel size.
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🔧 Tire Size Calculator
📊 Tire Dimensions
| Tire Height (Diameter) | 31.6 in | 803 mm |
| Wheel Size | 17 in | 432 mm |
| Sidewall Height | 7.3 in | 186 mm |
| Tire Width | 10.4 in | 265 mm |
| Tire Circumference | 99.3 in | 2,522 mm |
| Revolutions per Mile | 638.1 | |
| Revolutions per Kilometer | 396.5 | |
⚖️ Tire Size Comparison Calculator
Use this calculator to compare the sizes of two tires both numerically and visually.
Comparison Result
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Tire 1
265/70R17
|
Tire 2
265/40R23
|
Difference |
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Speedometer Difference:
📚 Tire Code Information
Tire Code
Car tires are described by an alphanumeric code, as shown in the figure below. Being able to read the tire code can be important, particularly when considering getting new wheels or tires, as being able to read the tire code is necessary for calculating things like tire size. Each part of the code describes some characteristic of the tire.
Intended Use
- P - Passenger car (cars, SUVs, crossovers, minivans)
- LT - Light truck (heavy loads, towing)
- ST - Special trailer (boat, utility trailers)
- T - Temporary (spare tires)
Size Components
- Width: Nominal section width in millimeters
- Aspect Ratio: Height to width ratio percentage
- Construction: R=Radial, D=Diagonal, B=Bias-belted
- Wheel Diameter: Rim size in inches
How is tire size calculated?
Section Height = Aspect Ratio × Tire Width
Tire Diameter = Wheel Diameter + 2 × Section Height
The aspect ratio and tire width are measurements acquired from the tire code. The tire width is the 3-digit number preceding the forward slash (/) in the tire code in units of millimeters. The aspect ratio is the 2- or 3-digit number immediately following the forward slash.
What to consider when changing tire/wheel size?
Tire decisions are important as they affect vehicle performance, safety, and efficiency. Consider these factors:
- Plus sizing: Generally recommended to stay within 3% of original diameter
- Speedometer accuracy: Different sizes affect odometer and speedometer readings
- Vehicle clearance: Ensure tires fit within wheel wells
- Load capacity: Maintain appropriate load rating for your vehicle
- Performance impact: Larger wheels may improve handling but reduce ride comfort