Reference
  • Jen
  • March 23, 2017

Metric to Standard Conversion

Enter the metric size (i.e. 285/75 R17)

15-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 15 inch Wheels
Metric Standard
215/75/15 27.7"x 8.5"
225/70/15 27.4"x 8.9"
225/75/15 28.3"x 8.9"
235/75/15 29.0"x 9.3"
245/75/15 29.5"x 9.6"
255/75/15 30.0"x 10.0"
265/75/15 30.6"x 10.4"

16-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 16 inch Wheels
Metric Standard
205/85/16 29.7"x 8.1"
215/75/16 28.7"x 8.5"
225/70/16 28.4"x 8.9"
225/75/16 29.2"x 8.9"
235/70/16 29.0"x 9.3"
235/85/16 31.7"x 9.3"
245/70/16 29.5"x 9.6"
245/75/16 30.5"x 9.6"
255/70/16 30.0"x 10.0"
265/70/16 30.6"x 10.4"
265/75/16 31.6"x 10.4"
275/70/16 31.2"x 10.8"
285/75/16 32.8"x 11.2"
295/75/16 33.4"x 11.6"
305/70/16 33.0"x 12.2"
315/75/16 34.8"x 12.4"
375/55/16 32.8"x 15.5"
395/70/16 37.9"x 16.0"

17-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 17 inch Wheels
Metric Standard
245/70/17 30.6"x 9.8
265/70/17 31.6"x 10.7
285/70/17 33.0"x 11.5
315/70/17 34.4"x 12.4

18-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 18 inch Wheels
Metric Standard
275/65/18 32.1"x 11.0
375/50/18 33.0"x 15.4
325/60/18 33.2"x 13.3
325/65/18 34.8"x 13.5
305/70/18 35.0"x 12.2
375/60/18 35.7"x 15.5
395/65/18 37.8"x 15.7

20-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 20 inch Wheels
Metric Standard
325/50/20 33.0"x 13.2"
Metric measurement example: 225/70R15
225 = Section width in millimeters
70 = Aspect ratio (ratio of section height to section width)
R15 = Rim diameter
R = Radial Construction, B = Bias Construction, D = Bias Belted Construction
Calculations for Measurements
Tire Width: Section width divided by 25.4 (Ex: 225 / 25.4 = 8.86")
Section Height: Tire width times aspect ratio (Ex: 8.86" x 70% = 6.20")
Overall Diameter: Section height times 2 plus rim diameter (Ex: (6.20" x 2) + 15 = 27.40")
Tags: 
Tires