This page contains all the tyre size calculators and converters that are spread amongst the Wheel & Tyre, all presented on a single page for quick reference.

The DOT Age Code Calculator:

This converter will turn your imperial tyre size into a metric tyre size:

Your imperial tyre size: X

Equivalent standard tyre size is : /100 R

Converting LT (Light Truck) imperial tyre sizes to metric:

Your LT tyre size: X R

Equivalent standard tyre size is : / R

Converting alpha numeric vintage tyre sizes to metric:

This calculator will convert alpha numeric vintage tyre sizes into the closest metric tyre size. Remember the section width is only a close approximations between old load and new size these days:
C = 185    D = 195    E = 205    F = 215    G = 225    H = 235 etc.

Your alphanumeric tyre size: ABCDEFGH R

Equivalent standard tyre size is: / R

Converting Michelin PAX tyre sizes to metric:

This calculator will convert Michelin PAX sizes into the closest metric tyre size.

Your PAX tyre size: / R

Standard tyre size is: / R

Comparing tyre sizes:

This calculator will help you to compare two different tyre sizes to see the differences in rolling circumference, and any speedometer difference error between the two sizes.

Current wheel/tyre	New wheel/tyre
145 150 155 165 175 185 190 195 205 215 225 230 235 245 255 265 275 285 295 305 315 325 335 395 / 25 30 35 40 45 50 55 60 65 70 75 80 82 85 100 R 12 13 14 15 15.5 16 16.5 17 18 19 19.5 20 21 22 23 24 25 26	145 150 155 165 175 185 190 195 205 215 225 235 245 255 265 275 285 295 305 315 325 335 395 / 25 30 35 40 45 50 55 60 65 70 75 80 82 85 100 R 12 13 14 15 16 16.5 17 18 19 19.5 20 21 22 23 24 25 26
Current rolling circumference mm	New rolling circumference mm
Difference in circumference:mm or%
So when your speedo reads 70mph, you're actually travelling atmph

Comparing wheel offsets:

This calculator will help you to understand how changing your wheel offset will affect the wheel's position in relation to your suspension and bodywork.

Current wheel/tyre	New wheel/tyre
Tyre Section: 145 155 165 175 185 190 195 205 215 225 230 235 245 255 265 275 285 295 305 315 325 335 395 Wheel offset: 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55	Tyre Section: 145 155 165 175 185 190 195 205 215 225 230 235 245 255 265 275 285 295 305 315 325 335 395 Wheel offset: 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

Calculating ideal rim width for any given tyre size:

This calculator will give you the ideal wheel rim size for any given tyre size.

Your tyre size: 145 155 165 175 185 195 205 215 225 230 235 245 255 265 275 285 295 305 315 325 335 / 30 35 40 45 50 55 60 65 70 75 80 85 R 12 13 14 15 15.5 16 16.5 17 18 19 19.5 20 21 22 23

Rim size is: X up to X