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

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.

Automotive

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.

Key differences

	Gear Ratio Calculator	Tire Size Converter
Category	Automotive	Automotive
Inputs required	2	3
Result	Gear Ratio (:1)	Overall Tire Diameter (inches)
What it does	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.	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.