Inch to Metric Tire Calculator — Convert Tire Sizes Easily

Inch to Metric Tire Calculator

Convert tire sizes between inch and metric measurements. Calculate tire diameter, width, sidewall height, circumference, and revolutions per mile.

Step 1: Input Tire Size

Understanding Tire Sizes

Metric format: 225/50R17 means 225mm width, 50% aspect ratio (sidewall height is 50% of width), and 17-inch rim. Inch format: 31×10.50R15 means 31-inch diameter, 10.5-inch width, and 15-inch rim.

Step 2: Calculation Options

Tire Size Impact

Changing tire size affects speedometer accuracy, acceleration, braking, fuel economy, and vehicle clearance. Always consult your vehicle manual before changing tire sizes.

Tire Size Conversion Results

Summary
Size Comparison
Specifications

Your Tire Size Conversion

225/50R17
Equivalent to: 26.9×8.9R17
225mm
26.9″
Overall Diameter
26.9 inches
Sidewall Height
4.4 inches
Circumference
84.5 inches
Revolutions per Mile
749

Tire Size Comparison

Tire Size Diameter Width Sidewall Circumference Revs/Mile

Detailed Tire Specifications

Width in Inches
8.9 inches
Width in Millimeters
225 mm
Diameter in Millimeters
683 mm
Circumference in Millimeters
2146 mm

Tire Size Conversion Formulas

Metric to Inch: Overall Diameter (inches) = (Width × Aspect Ratio ÷ 1270) + Rim Diameter
Inch to Metric: Width (mm) = Width (inches) × 25.4
Aspect Ratio (%) = (Overall Diameter – Rim Diameter) × 50 ÷ Width (inches)

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