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Gear Ratios by Spur Gear Size
Locate the spur gear size you want to know the ratios for then find the pinion gear size in the left column of that table. The ratio value is in the box to the right of the pinion gear.
If the sizes you wish to know the ratios for are not here simply divide the spur gear teeth by the pinion teeth. The ratio is the number of revolutions the pinion gear makes for every one revolution of the spur gear.

32 Pitch

Pinion 54 Tooth Spur
9T 6.00
10T 5.40
11T 4.90
12T 4.50
13T 4.15
14T 3.85
15T 3.60
16T 3.37
17T 3.17
18T 3.00
19T 2.84
20T 2.80
21T 2.70
22T 2.57
23T 2.45
24T 2.34
Pinion 56 Tooth Spur
9T 6.22
10T 5.60
11T 5.09
12T 4.66
13T 4.30
14T 4.00
15T 3.73
16T 3.50
17T 3.29
18T 3.11
19T 2.94
20T 2.80
21T 2.66
22T 2.54
23T 2.43
24T 2.33
Pinion 58 Tooth Spur
9T 6.44
10T 5.80
11T 5.27
12T 4.83
13T 4.46
14T 4.14
15T 3.86
16T 3.62
17T 3.41
18T 3.22
19T 3.05
20T 2.90
21T 2.76
22T 2.63
23T 2.52
24T 2.41
Pinion 60 Tooth Spur
9T 6.66
10T 6.00
11T 5.45
12T 5.00
13T 4.61
14T 4.28
15T 4.00
16T 3.75
17T 3.52
18T 3.33
19T 3.15
20T 3.00
21T 2.85
22T 2.72
23T 2.60
24T 2.50


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48 Pitch
Pinion 72 Tooth Spur
12T 6.00
13T 5.53
14T 5.14
15T 4.80
16T 4.50
17T 4.23
18T 4.00
19T 3.78
20T 3.60
21T 3.42
22T 3.27
23T 3.13
24T 3.00
25T 2.88
26T 2.76
27T 2.66
28T 2.57
29T 2.48
30T 2.40
Pinion 75 Tooth Spur
12T 6.25
13T 5.76
14T 5.35
15T 5.00
16T 4.68
17T 4.41
18T 4.16
19T 3.94
20T 3.75
21T 3.57
22T 3.40
23T 3.26
24T 3.12
25T 3.00
26T 2.88
27T 2.77
28T 2.67
29T 2.58
30T 2.50
Pinion 78 Tooth Spur
12T 6.50
13T 6.00
14T 5.57
15T 5.20
16T 4.87
17T 4.58
18T 4.33
19T 4.10
20T 3.90
21T 3.71
22T 3.54
23T 3.39
24T 3.25
25T 3.12
26T 3.00
27T 2.88
28T 2.78
29T 2.69
30T 2.60
Pinion 81 Tooth Spur
12T 6.75
13T 6.23
14T 5.78
15T 5.40
16T 5.06
17T 4.76
18T 4.50
19T 4.26
20T 4.05
21T 3.85
22T 3.68
23T 3.52
24T 3.37
25T 3.24
26T 3.11
27T 3.00
28T 2.89
29T 2.79
30T 2.70

48 Pitch

Pinion 85 Tooth Spur
12T 7.08
13T 6.53
14T 6.07
15T 5.66
16T 5.31
17T 5.00
18T 4.72
19T 4.47
20T 4.25
21T 4.04
22T 3.86
23T 3.69
24T 3.54
25T 3.40
26T 3.27
27T 3.14
28T 3.03
29T 2.93
30T 2.83
Pinion 87 Tooth Spur
12T 7.25
13T 6.69
14T 6.21
15T 5.80
16T 5.43
17T 5.11
18T 4.83
19T 4.57
20T 4.35
21T 4.14
22T 3.95
23T 3.78
24T 3.62
25T 3.48
26T 3.34
27T 3.22
28T 3.10
29T 3.00
30T 2.90
Pinion 90 Tooth Spur
12T 7.50
13T 6.92
14T 6.42
15T 6.00
16T 5.62
17T 5.29
18T 5.00
19T 4.73
20T 4.50
21T 4.28
22T 4.09
23T 3.91
24T 3.75
25T 3.60
26T 3.46
27T 3.33
28T 3.21
29T 3.10
30T 3.00
Pinion 93 Tooth Spur
12T 7.75
13T 7.15
14T 6.64
15T 6.20
16T 5.81
17T 5.47
18T 5.16
19T 4.89
20T 4.65
21T 4.42
22T 4.22
23T 4.04
24T 3.87
25T 3.72
26T 3.57
27T 3.44
28T 3.32
29T 3.20
30T 3.10
Pinion 96 Tooth Spur
12T 8.00
13T 7.38
14T 6.85
15T 6.40
16T 6.00
17T 5.64
18T 5.33
19T 5.05
20T 4.80
21T 4.57
22T 4.36
23T 4.17
24T 4.00
25T 3.84
26T 3.69
27T 3.56
28T 3.43
29T 3.31
30T 3.20


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64 Pitch

Pinion 100 Tooth Spur
20T 5.00
21T 4.76
22T 4.55
23T 4.35
24T 4.17
25T 4.00
26T 3.85
27T 3.70
28T 3.57
29T 3.45
30T 3.33
31T 3.23
32T 3.13
33T 3.03
34T 2.94
35T 2.86
36T 2.78
37T 2.70
38T 2.63
39T 2.56
40T 2.50
Pinion 104 Tooth Spur
20T 5.20
21T 4.95
22T 4.72
23T 4.52
24T 4.33
25T 4.16
26T 4.00
27T 3.85
28T 3.71
29T 3.58
30T 3.46
31T 3.35
32T 3.25
33T 3.15
34T 3.05
35T 2.97
36T 2.88
37T 2.81
38T 2.73
39T 2.66
40T 2.60
Pinion 108 Tooth Spur
20T 5.40
21T 5.14
22T 4.91
23T 4.70
24T 4.50
25T 4.32
26T 4.15
27T 4.00
28T 3.86
29T 3.72
30T 3.60
31T 3.48
32T 3.38
33T 3.27
34T 3.18
35T 3.09
36T 3.00
37T 2.91
38T 2.84
39T 2.77
40T 2.70
Pinion 111 Tooth Spur
20T 5.50
21T 5.28
22T 5.04
23T 4.82
24T 4.62
25T 4.44
26T 4.27
27T 4.11
28T 3.96
29T 3.82
30T 3.70
31T 3.58
32T 3.46
33T 3.36
34T 3.26
35T 3.17
36T 3.08
37T 3.00
38T 2.92
39T 2.84
40T 2.77

64 Pitch

Pinion 115 Tooth Spur
20T 5.75
21T 5.48
22T 5.23
23T 5.00
24T 4.79
25T 4.60
26T 4.42
27T 4.26
28T 4.11
29T 3.97
30T 3.83
31T 3.71
32T 3.59
33T 3.49
34T 3.38
35T 3.29
36T 3.19
37T 3.10
38T 3.02
39T 2.94
40T 2.87
Pinion 118 Tooth Spur
20T 5.90
21T 5.62
22T 5.36
23T 5.13
24T 4.91
25T 4.72
26T 4.53
27T 4.37
28T 4.21
29T 4.06
30T 3.93
31T 3.80
32T 3.68
33T 3.57
34T 3.47
35T 3.37
36T 3.27
37T 3.19
38T 3.10
39T 3.02
40T 2.95
Pinion 120 Tooth Spur
20T 6.00
21T 5.71
22T 5.46
23T 5.22
24T 5.00
25T 4.80
26T 4.62
27T 4.44
28T 4.29
29T 4.14
30T 4.00
31T 3.87
32T 3.75
33T 3.64
34T 3.53
35T 3.43
36T 3.33
37T 3.24
38T 3.15
39T 3.07
40T 3.00
Pinion 125 Tooth Spur
20T 6.25
21T 5.95
22T 5.68
23T 5.44
24T 5.21
25T 5.00
26T 4.81
27T 4.63
28T 4.46
29T 4.31
30T 4.17
31T 4.03
32T 3.91
33T 3.79
34T 3.68
35T 3.57
36T 3.47
37T 3.37
38T 3.29
39T 3.20
40T 3.12

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