275/45R21 tire size

A 275/45R21 tire is 30.74 in (780.9 mm) tall and 10.83 in (275.0 mm) wide, and turns 656 revolutions per mile.

• 30.74 inOverall diameter
• 4.87 inSidewall height
• 656Revolutions per mile
• 30.7x10.8R21Flotation equivalent

275/45R21 is a 21-inch tire with a 275 mm (10.83 in) section width and a 45% aspect ratio, giving a 4.87-inch sidewall and a flotation-style size of about 30.7x10.8R21.

Its overall diameter is 30.74 inches, so it rolls 96.6 inches per revolution and turns about 656 times per mile.

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

Compare 275/45R21 with plausible swaps

• 265/55R19 vs 275/45R21 (−0.87%)
• 275/55R19 vs 275/45R21 (+0.54%)
• 235/65R19 vs 275/45R21 (+0.92%)
• 255/60R19 vs 275/45R21 (+0.99%)
• 265/50R20 vs 275/45R21 (−1.01%)
• 295/45R20 vs 275/45R21 (−0.95%)
• 245/55R20 vs 275/45R21 (−0.44%)
• 305/45R20 vs 275/45R21 (+0.20%)
• 275/50R20 vs 275/45R21 (+0.27%)
• 255/55R20 vs 275/45R21 (+0.97%)
• 275/40R21 vs 275/45R21 (−3.52%)
• 255/45R21 vs 275/45R21 (−2.31%)
• 265/45R21 vs 275/45R21 (−1.15%)
• 275/45R21 vs 255/50R21 (+0.96%)
• 275/45R21 vs 285/45R21 (+1.15%)
• 275/45R21 vs 275/50R21 (+3.52%)
• 275/45R21 vs 305/35R22 (−1.10%)
• 275/45R21 vs 275/40R22 (−0.27%)
• 275/45R21 vs 285/40R22 (+0.76%)

Sizes within 3% of 30.74 in diameter

• 285/30R24 30.73 in (−0.04%)
• 305/45R20 30.81 in (+0.20%)
• 275/50R20 30.83 in (+0.27%)
• 275/40R22 30.66 in (−0.27%)
• 265/75R15 30.65 in (−0.31%)
• 235/75R17 30.88 in (+0.44%)
• 245/55R20 30.61 in (−0.44%)
• 265/70R16 30.61 in (−0.45%)
• 275/55R19 30.91 in (+0.54%)
• 265/65R17 30.56 in (−0.59%)
• 245/65R18 30.54 in (−0.67%)
• 265/60R18 30.52 in (−0.73%)
• 285/40R22 30.98 in (+0.76%)
• 245/70R17 30.50 in (−0.78%)
• 275/60R18 30.99 in (+0.81%)
• 31x10.50R15 31.00 in (+0.83%)
• 31x10.50R16 31.00 in (+0.83%)
• 265/55R19 30.48 in (−0.87%)
• 245/75R16 30.47 in (−0.90%)
• 235/65R19 31.03 in (+0.92%)
• 295/45R20 30.45 in (−0.95%)
• 255/50R21 31.04 in (+0.96%)
• 255/55R20 31.04 in (+0.97%)
• 255/60R19 31.05 in (+0.99%)
• 255/65R18 31.05 in (+1.00%)
• 255/70R17 31.06 in (+1.01%)
• 265/50R20 30.43 in (−1.01%)
• 275/65R17 31.07 in (+1.08%)
• 305/35R22 30.41 in (−1.10%)
• 215/85R16 30.39 in (−1.15%)
• 265/45R21 30.39 in (−1.15%)
• 285/45R21 31.10 in (+1.15%)
• 265/40R22 30.35 in (−1.29%)
• 295/40R21 30.29 in (−1.47%)
• 225/75R17 30.29 in (−1.49%)
• 305/30R24 31.20 in (+1.50%)
• 285/50R20 31.22 in (+1.55%)
• 295/40R22 31.29 in (+1.78%)
• 235/55R20 30.18 in (−1.84%)
• 235/60R19 30.10 in (−2.09%)
• 285/45R20 30.10 in (−2.10%)
• 265/45R22 31.39 in (+2.10%)
• 255/70R16 30.06 in (−2.24%)
• 265/50R21 31.43 in (+2.24%)
• 255/65R17 30.05 in (−2.25%)
• 255/60R18 30.05 in (−2.27%)
• 255/55R19 30.04 in (−2.28%)
• 255/50R20 30.04 in (−2.29%)
• 255/45R21 30.04 in (−2.31%)
• 255/40R22 30.03 in (−2.32%)
• 235/65R18 30.03 in (−2.33%)
• 285/60R18 31.46 in (+2.34%)
• 245/75R17 31.47 in (+2.36%)
• 265/55R20 31.48 in (+2.38%)
• 30x9.50R15 30.00 in (−2.42%)
• 275/60R17 29.99 in (−2.45%)
• 285/40R21 29.98 in (−2.50%)
• 235/70R17 29.95 in (−2.57%)
• 265/65R18 31.56 in (+2.66%)
• 275/55R18 29.91 in (−2.71%)
• 285/65R17 31.59 in (+2.74%)
• 265/70R17 31.61 in (+2.80%)
• 305/40R22 31.61 in (+2.80%)
• 235/75R16 29.88 in (−2.82%)
• 285/35R22 29.85 in (−2.89%)
• 265/75R16 31.65 in (+2.95%)
• 275/50R19 29.83 in (−2.98%)

Open 275/45R21 in the tire size calculator

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