What does wheel offset (ET) mean?

Offset (ET, from the German Einpresstiefe) is the distance in millimeters between the wheel's mounting face and its centerline. Positive offset means the mounting face sits toward the street side of the wheel, tucking the wheel inward. Lower or negative offset pushes the wheel outward toward the fender.

Do lower offset wheels stick out more?

Yes. Every 1 mm reduction in offset moves the entire wheel 1 mm outward. Width changes split the difference between both edges: going 1 inch wider adds 12.7 mm to each side before any offset change is applied.

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Wheel Offset Calculator

Compare your current wheels to a new set and see exactly how much further the new wheels poke out toward the fender - and tuck in toward the suspension.

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Wheel Specs

Current Width (inches)

Current Offset (mm ET)

New Width (inches)

New Offset (mm ET)

Outer Edge (Poke)
—
vs current wheel

Inner Edge (Clearance)

—

vs current wheel

Width Change

—

total

Offset Change

—

mm ET

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How Wheel Offset Works

Offset (stamped on the wheel as ET, e.g. ET35) is the distance in millimeters from the wheel's hub mounting face to its centerline. The mounting face is fixed to your hub - so offset and width together determine where both edges of the wheel end up.

Outer edge position = (Width in mm ÷ 2) − Offset

Inner edge position = (Width in mm ÷ 2) + Offset

Δ Poke = (New Width/2 − New ET) − (Old Width/2 − Old ET)

Width in millimeters is the advertised width × 25.4. Note that advertised width is measured bead-seat to bead-seat - the actual outer lip adds roughly half an inch per side, the same on both wheels, so it cancels out in a comparison.

Reading the Results

Poke positive - the new wheel's face sits further out toward the fender. Watch for fender-lip rub at full compression and legal fender-coverage rules in some states.
Inner clearance positive - the new wheel's inner edge sits closer to the strut, coilover, or control arm. More than ~5 mm closer warrants physically measuring your clearance; coilovers with large-diameter springs are the usual conflict.
A common recipe: going one inch wider while dropping offset ~13 mm puts all of the added width on the outside, keeping inner clearance unchanged.

The Tire Matters Too

This calculator compares the wheels. If you also change tire width, the tire's sidewall bulge moves the actual rub point - a 245 tire on a 9" wheel sits flatter than the same tire on an 8" wheel. Pair this with the Tire Size Calculator to check the diameter side of the equation.

Spacers

A spacer is functionally an offset reduction: a 12 mm spacer turns an ET35 wheel into an ET23. Use the calculator by subtracting the spacer thickness from your current offset. Hub-centric spacers preserve the wheel's centering ring fit; always re-check stud or bolt thread engagement after spacing.

Fitment Disclaimer

Whether a wheel "fits" depends on more than these numbers - suspension design, camber, ride height, fender shape, and tire choice all matter. Use this calculator to compare candidates, then confirm against a known-good fitment for your chassis from owners running the same setup.

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