Tire Size Calculator

Calculate tire diameter and circumference from width, aspect ratio, and wheel size.

Scratchpad (not saved)

mm
%
in

What This Calculator Does

Calculate tire diameter and circumference from width, aspect ratio, and wheel size.

It combines Width, Aspect Ratio, Wheel Diameter to estimate Overall Diameter, Circumference.

Formula & Method

Core equations: Sidewall height: h = W\cdot AR. Tire diameter: D = Rim + 2h. Circumference: C=\pi D.

Notation used in the formulas: R = Overall Diameter; x_{1} = Width; x_{2} = Aspect Ratio; x_{3} = Wheel Diameter.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use this calculator for quick scenario analysis. Start with baseline values, change one driver at a time, and compare how sensitive the results are to each input shown above.

Inputs Used

  • Width: Used directly in the calculation.
  • Aspect Ratio: Used directly in the calculation.
  • Wheel Diameter: Used directly in the calculation.

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