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Wheel Offset Calculator

Calculate wheel offset from total wheel width and the hub-mounting surface position measured from the inner edge.

Use the units shown beside each field. Decimal and scientific notation are accepted for non-integer fields; blanks, commas, fractions and non-finite entries are rejected.

Wheel centerline4.5 in
Offset31.75 mm
Offset1.25 in
Mounting surface position146.05 mm

The displayed results apply to the default example. Enable JavaScript to calculate other inputs.

How to use this calculator

  1. Replace the example values with measurements or ratings for the exact vehicle, circuit, component or system.
  2. Keep every value in the labeled unit and use manufacturer data where available.
  3. Select Calculate, then review the result together with the limitations and safety notes.

Formula and method

Centerline = overall width ÷ 2. Offset = mounting-surface distance from inner edge − centerline. Positive offset places the mounting surface outward.

Calculations run in your browser. Results are hidden whenever an input changes or validation fails, preventing an older result from being mistaken for a new calculation.

Worked example

Overall wheel width = 9 in; Mounting surface from inner edge = 5.75 in. The calculator returns Wheel centerline = 4.5 in; Offset = 31.75 mm; Offset = 1.25 in; Mounting surface position = 146.05 mm.

The worked example uses the same defaults shown in the interface, allowing the formula and displayed result to be checked together.

Limitations and safety

Wheel nominal width and measured overall width are not the same. Fitment also depends on tire size, brake clearance, suspension, load rating and manufacturer approval.

This is an educational planning model. Confirm ratings, tolerances, code requirements and safe procedures with manufacturers and qualified professionals before purchasing, modifying, wiring or operating equipment.

Frequently asked questions

What does positive offset do?

Positive offset moves the wheel centerline inward relative to the hub face, but actual clearance must be checked on the vehicle.

Why does the calculator reject my entry?

Each field shows its supported range. Whole-number fields reject decimals, and all fields reject blanks, words, comma-formatted numbers, fractions and non-finite values.

How should I use the displayed precision?

Keep extra digits while checking the calculation, then round to the precision supported by the measurements, component tolerances and published ratings.

Review notes and reference

Reviewed October 4, 2026. The formula and default example were checked together. The script was tested for defaults, input boundaries, invalid formats, condition-specific errors and recovery after an error. Reference: NHTSA TireWise safety guidance. Explanations and examples are original.

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