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Gear Ratio given Number of Teeth on Wheel and Pinion Calculator

Formula

The formula to calculate the Gear Ratio is:

$G = \frac{T}{Z_p}$

Where:

$G$ is the Gear Ratio
$T$ is the Number of Teeth on Wheel
$Z_p$ is the Number of Teeth on Pinion

Definition

The Gear Ratio is the ratio of output gear speed to the input gear speed or the ratio of the number of teeth on the gear to that on the pinion.

Example Calculation

Let's assume the following values:

Number of Teeth on Wheel ( $T$ ) = 12
Number of Teeth on Pinion ( $Z_p$ ) = 8

Using the formula:

$G = \frac{12}{8}$

Evaluating:

$G = 1.5$

The Gear Ratio is 1.5.

Conversion Chart

Number of Teeth on Wheel	Number of Teeth on Pinion	Gear Ratio
10	8	1.250000000000
11	8	1.375000000000
12	8	1.500000000000
13	8	1.625000000000
14	8	1.750000000000
15	8	1.875000000000
16	8	2.000000000000
17	8	2.125000000000
18	8	2.250000000000
19	8	2.375000000000
20	8	2.500000000000

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