Tire Size Calculator – Convert Tire Diameter, Height to Inches

Tire Size Calculator

tire size calculator

Overall Diameter
Tread Width
Rim Diameter
Sidewall Height
Section Width
Tire Size
Tire Circumference

Tire Size Conversion Explained

Tire Width Calculator

Tire width is measured at its thickest point, the distance between the inner sidewall’s and the outer sidewall’s widest point, also known as section width or tread width.

E.g. 235/70R15: Tire Width = 235 mm (9.6 In.)

tread width
Tire Width

Tire Sidewall Height Calculator

Tire Sidewall Height is measured from the rim to the outer edge of the tire’s tread, expressed as a percentage of tire width.

Sidewall Height = (Tire Width*Aspect Ratio)/100

E.g. 235/70R15: Sidewall Height = (275*70)/100 = 192.5 mm (7.6 in.)

sidewall height
Sidewall Height

Rim/Wheel Height Calculator

Rim/Wheel Height is measured from the rim to the outer edge of the tire’s tread, expressed as a percentage of tire width.

E.g. 235/70R15 Rim Height = 15 In.

Rim Diameter
Rim Height

Tire Diameter Calculator

Tire Diameter is measured from the bottom to the highest point at the top of a tire through its exact center when inflated and no load.

Tire Diameter = Rim Height + 2*Sidewall Height

E.g. 235/70R15: Tire Diameter = 15 + 2*7.6 = 30.2 In.

Tire Diameter
Tire Diameter

Tire circumference Calculator

Tire circumference is measured of the distance the tire covers in one full rotation.

Circumference = Tire Diameter x 3.14

E.g. 235/70R15: Circumference = 30.2*3.14 = 94.8 In.


Tire Revolutions Calculator

The performs revs/mile. Revolutions per mile indicate the number of times a tire rotates while it covers the distance of one mile.

Revs/mile = 63,360/Circumference

E.g. 235/70R15: Revs/mile = 63,360/94.8 = 668.4


Popular Tire Size Conversions

*Disclaimer: Please note that our tire dimensions & measurements are an approximation number, while the tire manufacturers may have different ways in calculating or rounding numbers. We recommend referring to the vehicle manufacturer’s manual or checking with the tire technician to find out the correct tire size for your vehicle.