Tire Size Conversion
235/45r18 to inches
Precise conversion of tire size 235/45r18: section width, sidewall height, overall diameter, circumference, and revolutions per mile. Includes exact mm ↔ inches results and quick guidance.
Section width
235 mm
9.25 inches
Sidewall height
105.8 mm
4.16" (45% of width)
Wheel (rim) diameter
18"
457.2 mm
Overall diameter
26.33"
668.7 mm
Circumference
82.71"
2100.8 mm
Revolutions per mile/km
766 revs/mile
476 revs/km
About 235/45r18 tire size
The size 235/45r18 indicates a section width of 235 mm (9.25 inches), an aspect ratio of 45% (sidewall height 105.8 mm or 4.16 inches), and a 18-inch wheel. Overall diameter calculates to 26.33 inches (668.7 mm), with circumference 82.71 inches.
Use these measurements to estimate speedometer error and clearance changes when switching sizes. For multi-size comparison and speed error calculation, try our dedicated tire size calculator.
Common tire sizes
Compare 235/45r18 with other popular tire sizes to find the perfect fit for your vehicle.