Wheel offset
calculator
See how far a new wheel will sit in or out compared with your current wheel before buying it.
Last checked 12 October 2026Published by Sidewall GuideFormulas follow the Tire and Rim Association and ETRTO size conventions
Editorial record
Noam Cohen wrote and checked this calculator’s formulas. Published by Sidewall Guide. Last checked 12 October 2026.
No independent technical reviewer is listed. The result estimates wheel edge movement from nominal dimensions; it cannot confirm vehicle fitment or clearance.
Reference organizations
These organizations publish tire and rim standards. They are reference context; neither endorses nor independently reviews this calculator.
Starting specification
Current wheel
The wheel’s bead-seat width, measured in inches; assumes the marked wheel width.
Distance from the wheel centerline to its mounting face; positive means the face is toward the road.
Proposed specification
New wheel
The new wheel’s bead-seat width in inches; assumes the marked wheel width.
Distance from the new wheel centerline to its mounting face; positive means toward the road.
Enter your current and new wheel to see how far the new one sits in or out.
Calculation method
How this is calculated
Wheel geometry
Formulas
- Backspacing (in) = (wheel width (in) + 1) ÷ 2 + offset (mm) ÷ 25.4.
- Inner edge movement (mm) = (current backspacing − new backspacing) × 25.4; positive means further from the suspension.
- Outer edge movement (mm) = (new width − current width) × 12.7 − (new offset − current offset).
- Wheel width and edge positions are approximate and assume nominal wheel dimensions.
These references describe tire and rim dimensions and industry conventions. They do not validate this calculator’s estimates for a specific wheel or vehicle; the movement formulas above are published here with their assumptions.
Assumptions
- Wheel width is the nominal bead-seat width; actual wheel lips extend beyond it.
- The calculation compares wheel position only and does not confirm brake, suspension or body clearance.
Sources
The Tire and Rim Association
No independent technical review or consumer rating is represented. See the full methodology and source list.