Wheel offset calculator
Compare nominal inner intrusion, outer protrusion and inner-clearance changes between two wheel widths and offsets.
Widths are nominal bead-seat widths from 0.1 to 40 inches. Signed offsets are -500 to +500 mm. Positive offset places the mounting face outboard of the centerline. Positive inner intrusion reduces inner clearance; positive outer protrusion moves outward. Both wheels use the same mounting plane. Tire bulge, flange widths, spacers, brakes and suspension motion are excluded. These nominal position changes do not establish fitment, safety, vehicle approval or legality. Processing stays on your device in a cancellable worker with a 10-second timeout. Maximum 500000 combined input characters and 2000 records, with 30 tariffs or grades, 30 tiers per tariff and 100 depreciation years. Guided decimals allow up to six places without thousands separators. Full JSON and JSON Pointer CSV include all source inputs, units, assumptions and results; each file is capped at 2000000 characters and CSV at 200000 leaf records. All tariff totals precede the first 200 detail rows in the parking preview; other tables preview 200 rows. Software bounds are not vehicle capability claims. Results use floating-point arithmetic. Up to 500,000 characters. Review the settings before running.
Your result
How to use Wheel offset calculator
- Enter the current wheel nominal width in inches and signed offset in millimetres.
- Enter the proposed width and offset using the same mounting-plane assumption.
- Review the signed inner and outer changes, then download the full comparison.
Useful next steps
Understand the signs
Nominal inner extent is half the width in mm plus offset; outer extent is half the width minus offset. Each reported change is proposed minus current. Positive inner intrusion reduces inner clearance, while positive outer protrusion moves outward.
Keep the comparison geometric
An inch is exactly 25.4 mm. Nominal wheel width is measured between bead seats, not across the outside flanges. This model excludes tire bulge, flange geometry, spacers, brake clearance and suspension motion. It does not establish fitment, safety, approval or legality.