FIRST-PARTY TOOL · NO GUESSWORK IN THE MATH
Tire Size Comparison
See how two tire sizes compare before requesting a quote.
For your daily driver, work truck, trailer or equipment. Enter the size on each tire below.
Calculated dimensions, not verified fitment. Similar dimensions do not prove that a tire or wheel is suitable for your vehicle or equipment.
Not sure what tire size you have?
Look on the tire sidewall, the vehicle tire placard where applicable, or the equipment placard/manual. Check front and rear tires separately. An existing tire is useful information, but may not be the original or correct size.
Sizes such as 7.00-15, 4.80-12 and 9.50R16.5 cannot be calculated here from the marking alone. Use the exact tire’s published dimensions, or text us a photo. See where to find your tire size.
How the calculations work
Metric sizes: sidewall height = section width × aspect ratio ÷ 100; convert millimeters to inches by dividing by 25.4. Overall diameter = rim diameter + twice the sidewall height. Three-number inch sizes supply diameter, width and rim; sidewall height = (diameter − rim) ÷ 2.
Circumference = π × overall diameter. Theoretical revs/mile = 63,360 ÷ circumference in inches. Speed examples multiply indicated speed by the considering/current circumference ratio. Values keep full precision internally; dimensions and differences display up to two decimals, speeds and revs/mile one. Rounding can hide very small differences.
Manual entries use the dimensions you supply and do not verify the tire’s construction, measuring conditions or application. Future manufacturer specifications will remain separate from these calculated results.