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Enter the serial number from the pocket watch movement below. Do not use the case number. Tips for looking up your watch

How to Find Info About Your Pocket Watch

The Pocket Watch Database has compiled data covering the major American pocket watch manufacturers and created an easy way to find information using the serial number on the watch movement. Here are a few tips to find information about your pocket watch:

  1. Always input the serial number from the pocket watch movement (the "mechanism" of the watch).
  2. Never use the serial number from the case or any other part.
  3. Always select the correct manufacturer, which is usually stamped on the watch movement or dial.
  4. If the manufacturer is not listed on the site, you may have a "private label" watch or it may not be American-made.
  5. If the serial number includes a letter, enter it along with the number when using the lookup feature.
  6. Many pocket watch case backs screw off. Others may require a dull wide blade to pry or pop the cover. Be careful not to scratch or damage the movement.
  7. Consider uploading images of your watch by creating a collection account on the website. This is compeltely free and assists in promoting research in American horology.
  8. Understand that many companies did not keep accurate or complete records. As a result, information displayed on this site may have inaccuracies. This is to be expected, and we have included an option to report inaccurate information on the result pages so the database can be continually improved.
Pocket Watch Serial Number Lookup - Hamilton, South Bend, Illinois, Rockford, Waltham & Elgin Pocket Watches
  Serial Number:
Need to replace a watch crystal? Use our new crystal size guide to find the proper fit.


Pocket Watch Size Chart

Use the size chart below to determine the size of your watch by carefully measuring the pillar plate (dial side) diameter of the movement with a micrometer.

The sizing system utilized by American watch companies is derived from the Lancashire Gauge, popularized in the English watchmaking trade. One inch is taken as a basing figure and 5/30 of an inch is added for the fall or drop of the dial, resulting in 1 5/30 of an inch referred to as "naught size” (0s). Subsequently, the addition or subtraction of each 1/30” increment results in scaling the size up or down. For example, size 12 measures 1 17/30” (12 increments of 1/30” from the naught size of 1 5/30”).

Note: Companies did not strictly adhere to this sizing standard, using a 6/30" drop instead of the 5/30" for larger movements. As a result, “18 Size” American movements are actually 19 Size according to the Lancashire Gauge system.


= Standard Size Utilized by American Companies
Size Diameter (Millimeters) Diameter (Inches) Diameter (Inches, Fraction)
21/0s 12.70 mm 0.500 in 1/2 in
20/0s 13.55 mm 0.533 in 8/15 in
19/0s 14.39 mm 0.567 in 17/30 in
18/0s 15.24 mm 0.600 in 3/5 in
17/0s 16.09 mm 0.633 in 19/30 in
16/0s 16.93 mm 0.667 in 2/3 in
15/0s 17.78 mm 0.700 in 7/10 in
14/0s 18.63 mm 0.733 in 11/15 in
13/0s 19.47 mm 0.767 in 23/30 in
12/0s 20.32 mm 0.800 in 4/5 in
11/0s 21.17 mm 0.833 in 5/6 in
10/0s 22.01 mm 0.867 in 13/15 in
9/0s 22.86 mm 0.900 in 9/10 in
8/0s 23.71 mm 0.933 in 14/15 in
7/0s 24.55 mm 0.967 in 29/30 in
6/0s 25.40 mm 1.000 in 1 in
5/0s 26.25 mm 1.033 in 1 1/30 in
4/0s 27.09 mm 1.067 in 1 1/15 in
3/0s 27.94 mm 1.100 in 1 1/10 in
2/0s 28.79 mm 1.133 in 1 2/15 in
0s 29.63 mm 1.167 in 1 1/6 in
1s 30.48 mm 1.200 in 1 1/5 in
2s 31.33 mm 1.233 in 1 7/30 in
3s 32.17 mm 1.267 in 1 4/15 in
4s 33.02 mm 1.300 in 1 3/10 in
5s 33.87 mm 1.333 in 1 1/3 in
6s 34.71 mm 1.367 in 1 11/30 in
7s 35.56 mm 1.400 in 1 2/5 in
8s 36.41 mm 1.433 in 1 13/30 in
9s 37.25 mm 1.467 in 1 7/15 in
10s 38.10 mm 1.500 in 1 1/2 in
11s 38.95 mm 1.533 in 1 8/15 in
12s 39.79 mm 1.567 in 1 17/30 in
13s 40.64 mm 1.600 in 1 3/5 in
14s 41.49 mm 1.633 in 1 19/30 in
15s 42.33 mm 1.667 in 1 2/3 in
16s 43.18 mm 1.700 in 1 7/10 in
17s 44.03 mm 1.733 in 1 11/15 in
18s 44.87 mm 1.767 in 1 23/30 in
Note: American 18s Movements Measure 1.800" Due to the Increased 6/30" Drop.
19s 45.72 mm 1.800 in 1 4/5 in
20s 46.57 mm 1.833 in 1 5/6 in
21s 47.41 mm 1.867 in 1 13/15 in
22s 48.26 mm 1.900 in 1 9/10 in
23s 49.11 mm 1.933 in 1 14/15 in
24s 49.95 mm 1.967 in 1 29/30 in
25s 50.80 mm 2.000 in 2 in
26s 51.65 mm 2.033 in 2 1/30 in
27s 52.49 mm 2.067 in 2 1/15 in
28s 53.34 mm 2.100 in 2 1/10 in
29s 54.19 mm 2.133 in 2 2/15 in
30s 55.03 mm 2.167 in 2 1/6 in
31s 55.88 mm 2.200 in 2 1/5 in
32s 56.73 mm 2.233 in 2 7/30 in
33s 57.57 mm 2.267 in 2 4/15 in
34s 58.42 mm 2.300 in 2 3/10 in
35s 59.27 mm 2.333 in 2 1/3 in
36s 60.11 mm 2.367 in 2 11/30 in