Calculate metric or inch tyre dimensions and compare to similar tyre sizes. Use the comparison tab to see side by side comparison and speedometer error.

Use our tyre size calculator to calculate the diameter, width, sidewall, circumference, and revolutions per mile of any tyre. Just type in a metric or standard size tyre and click calculate. Inch measurement tyres are fairly easy to understand however metric tyres use a more difficult system to read. The first number on a metric tyre is the width. Divide this by 25.4 to get inch equivalent. The third number generally preceded by an "R" is the wheel diameter. The sidewall and aspect ratio are used in metric sized tyres to determine the overall height of a tyre. The second number on a metric tyre is to calculate the side wall measurement. The sidewall height is a percentage of the width of the tyre. This second number is that percent. The sidewall height or "aspect ratio" of a 285/75/R16 tyre is 75% of 285mm.

To calculate a metric tyre to height in inches: (#1 x #2 / 2540 x 2) + (#3)

Example: 285/75R16 (285 X 75 / 2540 x 2) + 16 = 32.8 inches tall.

Our tyre calculator makes this happen for you. Just type in the metric fields and click convert to inches. It also solves the problem of deciding what tyre you would like to run if you have inch measurements in mind but can't find a company that manufactures that inch size tyre. Just fill in the inch measurements you are looking for and it will calculate and exact metric version of that tyre. There are many more possibilities and choices in metric tyres so the use of a tyre size calculator can come in handy.

The tire size comparison calculator takes the measurements of two tyres and compares the diameter, width, sidewall, circumference, and revolutions per mile. Then as a bonus it shows examples of your speedometer reading with the first tyre, and the actual speed you"re traveling if you were to install the second tyre. A very useful tyre calculator when searching for tyres that are a different size then stock.

A tyre size conversion calculator or tyre diameter calculator are the best ways to get the answers you are looking for. What sets us apart is our tyre suggestion guide. For each tyre size you input our tyre calculator suggests multiple tyre sizes that are with in one inch bigger and smaller of the entered tyre size. Making it as simple as possible to find the tyre that is just right for you.

Also browse our tyre categories and deals pages for Jeep tyres, 4X4 tyres, cheap new tyres, all weather tyres, cheap truck tyres, all season tyres, and tyres with free shipping.

Tyre Size Calculator Charts by Wheel Size

Tyre Size Calculation Charts by Diameter