Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Tire Size Converter

Convert a metric tire size (width, aspect ratio, and wheel diameter) into overall tire diameter in inches. Use this when comparing tire sizes, checking fitment, or calculating speedometer error after a tire change.

Tire Width (mm)

Aspect Ratio (%)

Wheel Diameter (inches)

Fill in the required fields to see your result.

Automotive

Gear Ratio Calculator

Calculate the gear ratio between two meshing gears using their tooth counts. Useful for designing drivetrains, bicycles, RC vehicles, and any mechanical power-transmission system.

Input Gear Teeth (teeth)

Output Gear Teeth (teeth)

Fill in the required fields to see your result.

Key differences

	Tire Size Converter	Gear Ratio Calculator
Category	Automotive	Automotive
Inputs required	3	2
Result	Overall Tire Diameter (inches)	Gear Ratio (:1)
What it does	Convert a metric tire size (width, aspect ratio, and wheel diameter) into overall tire diameter in inches. Use this when comparing tire sizes, checking fitment, or calculating speedometer error after a tire change.	Calculate the gear ratio between two meshing gears using their tooth counts. Useful for designing drivetrains, bicycles, RC vehicles, and any mechanical power-transmission system.