By entering tire width, the aspect ratio, and wheel diameter this calculator spits out the height of your tire. The width is the first number on the tire 255, 265, 285 etc. The aspect ratio is the next number in the line. It’s a two-digit number that represents the sidewall thickness/height of the tire as a percentage of the width. The wheel size is the last number in the tire size, often preceded by an ‘R’. Simply plug in the numbers off the tire and hit the ‘Solve’ button and your tire height will appear in the box below. This calculator is generally used in conjunction with our RPM Calculator and Transmission Ratio RPM Calculator.