Wheel Offset/Backspace Calculator will help you to find the wheel offset and the backspace.

The wheel offset and backspace are important measurements for positioning the wheel/tyre assembly inside the wheel well. It will help you to determine which wheels are adequate for your car. This calculator also gives the option to compare wheels, to compare the offset and the backspace of one or more additional wheels to the base wheel.

Below the calculator there are detailed instructions how to use this calculator.

Find out more about Wheel offset and backspace.

Wheel Offset/Backspace Calculator

enter overall wheel width


enter backspace or offset


Wheel dimensions

Width - -
Lip Width - -
- -
Frontspace - -

This button will be enabled when you've got dimensions for at least one more wheel, besides the first entered in the calculator.

After you click on this button, the last calculated wheel dimensions will be added for the comparision in the "Comparing Wheels" form below.

Comparing Wheels

Measurement units

Base Wheel
- -
Offset - -
Backspace - -
Frontspace - -

To compare another two wheels click on the button "Clear Compared Wheels". To start over, with a new data for the base wheel - please refresh the page.

The calculator results should be verified with the wheel manufacturer. This is for informative purposes only. The tyresizecalculator.com is not responsible for any miscalculations of this calculator or any errors that may arise with its usage.


Try out our Wheel/Rim Size Calculator which shows the acceptable wheel width range for any given tyre size.

Tyre size for rim size/width calculator tells you what tyre sizes to go for, for the size of your rim.

Tire size converter can help you to convert the inch tire size (Standard, English measuring system) to the metric tire size and the other way around. The converter also displays adequate actual tires with the dimensions which are closest to the calculated tire size, if such exist.

Related articles:

How to use the wheel offset/backspace calculator?

Our calculator is divided into two sections:

Section "enter overall wheel width" gives you an option to input the overall wheel width directly into the form field "measured overall width" or you can enter the declared wheel width and the lip width and the calculator will calculate the overall wheel width based on these two measurements. You can choose between these two options. Default lip width is set to a ½ inch.

Section "enter backspace or offset" allows you to choose which measurement you want to enter: backspace or offset. If you wanted to find out the offset you would choose to enter the backspace, conversely if you wanted to find out the backspace you would choose to enter the offset.

After you click the button "Calculate ..." all wheel dimensions will be presented, in the table below the calculator.

This calculator also gives the option to compare wheels, to compare the offset and the backspace for two additional wheels to the base wheel - the first wheel entered into the calculator which is the basis for the comparision. After you've got dimensions for the second wheel, the "Compare this wheel" button will be enabled, so you can click on it and add that wheel for a comparision into the form "Comparing wheels". In that form, besides the data for the base wheel, every compared wheel, with its dimensions, is contained in a section "Compared wheel x" and it has the column "Diff" which shows the calculated differences for its dimensions, compared to the base wheel.