Metric to Inch Tire Size Converter

By February 11, 2015Calculators, Wheels

Calculator

Enter your tire size information into one side of the tire size converter below to convert metric tire sizes to inches or inch tire sizes to their metric equivalents.

Metric Tire Size

/ R
(Example: 315 / 75 R 16)

Inch Tire Size

x -
(Example: 35 x 12.50 - 16)

What’s the Difference?

Most of us are used to reading metric tire dimensions even though they are a little harder to visualize. For instance, a 315/75R16 tire is 315 mm wide with a sidewall height that’s 75% of its width for a 16-inch wheel.

When you get into larger tire sizes (those over 35″ in diameter), you begin seeing more SAE sizes instead which are easier to understand. A 35×12.50-16 tire runs 35 inches tall and 12.5 inches wide for a 16-inch wheel.

Converting a metric tire to inches can be done with the equation below, but the calculator is much easier!

Conversion Formula

[315] / [75] R [16] = [ (Tire Width x Aspect Ratio x 2) / 2550 + Wheel Diameter ] x [ Tire Width / 25.4 ] – [ Wheel Diameter ] = [35] x [12.4] – [16]

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