Wheel Offset Calculator | Fitment & Clearance Preview

Wheel Offset Calculator

Compare current and new wheel widths and offsets to see how inner (toward suspension) and outer (toward fender) positions will change. Results shown in millimetres and inches.

Units for wheel width

Current wheel Wheel width Offset (ET) — positive towards outside (mm)

New wheel Wheel width Offset (ET) — positive towards outside (mm)

Formula summary: convert widths to millimetres (1 in = 25.4 mm). Centerline = width_mm / 2. Outer distance from hub face = centerline – offset. Inner distance from hub face = centerline + offset. Differences show how much the wheel moves inwards or outwards.

Quick guidance

Positive outer change means the wheel moves outward (closer to fender).
Positive inner change means the wheel moves inward (closer to suspension).
Check for rubbing on fender (outer) and clearance with brakes/suspension (inner).
Remember tyre overall diameter and backspacing also affect fitment.

What is a Wheel Offset Calculator?

A Wheel Offset Calculator is a tool that helps you determine how different wheel sizes and offsets will fit your vehicle. It calculates the position of the wheel relative to the hub mounting surface and the fender. Whether you are upgrading your car’s wheels for better performance, appearance, or clearance, knowing the correct wheel offset ensures safety, proper alignment, and a perfect fit.

Understanding Wheel Offset

Wheel offset is the distance between the wheel’s centerline and the hub mounting surface. It is usually measured in millimeters and can be positive, negative, or zero.

Positive Offset: The hub mounting surface is toward the outside (front) of the wheel. Most modern cars use positive offsets.
Negative Offset: The hub mounting surface is toward the inside (rear) of the wheel, giving the wheel a deeper dish look.
Zero Offset: The hub mounting surface is exactly at the centerline of the wheel.

Why Use a Wheel Offset Calculator?

Using a wheel offset calculator helps you:

Check if new wheels will clear your suspension and fenders.
Avoid rubbing or handling problems.
Ensure proper alignment and braking performance.
Compare your current and new wheel setups before buying.

By inputting your current and desired wheel widths and offsets, the calculator quickly shows how the wheel position changes—both inside (toward suspension) and outside (toward fender).

How to Use the Wheel Offset Calculator

Enter your current wheel width and offset.
Enter the new wheel width and offset you want to compare.
Click “Calculate.”
You’ll instantly see how much the inner and outer positions change. This helps you visualize fitment and make safe choices for your vehicle.

Conclusion

A Wheel Offset Calculator is an essential tool for anyone upgrading their wheels or tires. It ensures your new setup fits correctly, preventing costly mistakes and improving both the performance and appearance of your car.