305/70R18 tire size

A 305/70R18 tire is 34.81 in (884.2 mm) tall and 12.01 in (305.0 mm) wide, and turns 579 revolutions per mile.

• 34.81 inOverall diameter
• 8.41 inSidewall height
• 579Revolutions per mile
• 34.8x12.0R18Flotation equivalent

305/70R18 is a 18-inch tire with a 305 mm (12.01 in) section width and a 70% aspect ratio, giving a 8.41-inch sidewall and a flotation-style size of about 34.8x12.0R18.

Its overall diameter is 34.81 inches, so it rolls 109.4 inches per revolution and turns about 579 times per mile.

20 other sizes in this list are within 3% of that diameter.

Compare 305/70R18 with plausible swaps

• 315/75R16 vs 305/70R18 (−0.60%)
• 285/75R17 vs 305/70R18 (−2.82%)
• 315/70R17 vs 305/70R18 (−1.29%)
• 35x11.50R17 vs 305/70R18 (+0.54%)
• 35x12.50R17 vs 305/70R18 (+0.54%)
• 315/75R17 vs 305/70R18 (+2.27%)
• 285/70R18 vs 305/70R18 (−3.17%)
• 295/70R18 vs 305/70R18 (−1.58%)
• 305/70R18 vs 285/75R18 (+0.06%)
• 305/70R18 vs 35x12.50R18 (+0.54%)
• 305/70R18 vs 315/70R18 (+1.58%)
• 305/70R18 vs 295/60R20 (−2.51%)
• 305/70R18 vs 275/65R20 (−2.11%)
• 305/70R18 vs 315/60R20 (+0.20%)
• 305/70R18 vs 35x12.50R20 (+0.54%)
• 305/70R18 vs 35x13.50R20 (+0.54%)
• 305/70R18 vs 325/60R20 (+1.56%)

Sizes within 3% of 34.81 in diameter

• 325/50R22 34.80 in (−0.05%)
• 285/75R18 34.83 in (+0.06%)
• 315/60R20 34.88 in (+0.20%)
• 35x11.50R17 35.00 in (+0.54%)
• 35x12.50R24 35.00 in (+0.54%)
• 35x12.50R15 35.00 in (+0.54%)
• 35x12.50R17 35.00 in (+0.54%)
• 35x12.50R18 35.00 in (+0.54%)
• 35x12.50R20 35.00 in (+0.54%)
• 35x13.50R20 35.00 in (+0.54%)
• 35x12.50R22 35.00 in (+0.54%)
• 315/75R16 34.60 in (−0.60%)
• 315/70R17 34.36 in (−1.29%)
• 325/60R20 35.35 in (+1.56%)
• 295/70R18 34.26 in (−1.58%)
• 315/70R18 35.36 in (+1.58%)
• 275/65R20 34.07 in (−2.11%)
• 315/75R17 35.60 in (+2.27%)
• 295/60R20 33.94 in (−2.51%)
• 285/75R17 33.83 in (−2.82%)

Open 305/70R18 in the tire size calculator

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.