Tire Size Calculator & Offset

Compare tire sizes, speedometer error, plus sizes and wheel offset (ET) in mm

Tire Size Calculator compares two tire sizes and shows what changes: overall diameter, sidewall, circumference, ride height, speedometer error and, new in this version, wheel offset and rim width.▶ TIRE SIZE COMPARISON• Current vs new size, e.g. 225/45R17 → 235/40R18 or 265/70R17 → 33x12.50R17• Overall diameter, sidewall height, circumference, ride height, revs per km or mile• Both tires drawn to scale on one pictur…