How the wheel offset calculator works
Offset (ET) is the distance in millimeters from the wheel's centerline to the hub mounting face. A higher offset pulls the wheel in toward the suspension; a lower one pushes it out toward the fender. Width matters too: an extra half inch of width adds about 6.35 mm on each side.
- Outward change (poke) = (new width ÷ 2 − new ET) − (old width ÷ 2 − old ET)
- Toward the strut = (new width ÷ 2 + new ET) − (old width ÷ 2 + old ET)
- Speedometer: a taller tire makes the speedometer read low. The calculator shows your real speed at an indicated 60 mph.
For a real fit check, measure the gap from your current tire to the fender lip and to the strut, enter both, and the calculator subtracts the change. Open the full wheel offset calculator →
Will these wheels fit? A quick checklist
- Bolt pattern and center bore match your hub (or use hub-centric rings). Look them up with the bolt pattern lookup.
- Outer change is within your measured fender gap, with room for suspension compression.
- Inner change leaves at least a few millimeters to the strut, spring perch and control arms.
- The wheel's spoke design clears your brake calipers.
- The tire's overall diameter is within about 3% of stock to limit speedometer and ABS issues.
Compare tire sizes side by side with the tire size calculator. For indicated speed after a size change, use the speedometer error calculator; for RPM and effective gearing, use the gear ratio & RPM calculator.
Exhaust sound simulator
Pick an engine layout and exhaust style, start the engine and rev it with the throttle slider. The sound is synthesized in your browser from the engine's firing frequency, so you can compare the character of stock, cat-back and open race setups. It is an approximation, not a recording of any brand's product.
Before you buy: in the US it is illegal to remove or bypass catalytic converters or other emissions equipment on a road vehicle, and many states limit exhaust noise. California's limit for most passenger cars is 95 dBA. Open the sound lab →
Car wrap cost and color preview
Try wrap colors, ride height, wheel finish and tint on the preview, then estimate the material and labor cost for your vehicle size. Open the car wrap cost calculator → For paint protection film, use the PPF cost calculator.
Car modification cost calculator
The mod cost tab totals parts, estimated install hours and labor at your local shop rate, with a DIY-only total for comparison. All figures are planning estimates; prices vary by vehicle, brand and region. Open the mod cost calculator →
FAQ
How do I know if new wheels will fit my car?
Enter your current and new wheel width, offset and tire sizes, then add the fender and strut gaps you measured. If the remaining clearance is under about 5 mm, expect rubbing under load or at full lock.
What does a lower wheel offset do?
For the same width, each 1 mm lower offset moves the wheel 1 mm outward, increasing poke and track width and moving the wheel away from the strut.
Is the exhaust sound real?
No. It is generated live from engine type and RPM to show the general character of a change.