The serial number on a Patek Philippe watch can be found in different places, but it is always engraved somewhere on the case back. If it has a see-through case back, it may be engraved on the movement or on the side of the case back.
| YEAR | SERIAL |
|---|---|
| 1840 | 100 |
| 1845 | 1,200 |
| 1850 | 3,000 |
| 1855 | 8,000 |
| 1860 | 15,000 |
| 1865 | 22,000 |
| 1870 | 35,000 |
| 1875 | 45,000 |
| 1880 | 55,000 |
| 1885 | 70,000 |
| 1890 | 85,000 |
| 1895 | 100,000 |
| 1900 | 110,000 |
| 1905 | 125,000 |
| 1910 | 150,000 |
| 1915 | 175,000 |
| 1920 | 190,000 |
| 1925 | 200,000 |
| 1950 | 700,000 |
| 1955 | 725,000 |
| 1960 | 750,000 |
| 1965 | 775,000 |
| 1970 | 795,000 |
| 1950 | 930000 |
| 1955 | 940000 |
| 1920 | 800,000 |
| 1925 | 805,000 |
| 1930 | 820,000 |
| 1935 | 824,000 |
| 1940 | 835,000 |
| 1945 | 850,000 |
| 1950 | 860,000 |
| 1955 | 870,000 |
| 1960 | 880,000 |
| 1965 | 890,000 |
| 1970 | 895,000 |
| 1940 | 900,000 |
| 1945 | 915,000 |
| 1950 | 882,335 |
| 1955 | 882,553 |
| 1960 | 960,000 |
| 1965 | 975,000 |
| 1970 | 995,000 |
| 1960 | 1,100,000 |
| 1965 | 1,130,000 |
| 1970 | 1,250,000 |
| l975 | 1,350,000 |
| 1980 | 1,450,000 |
| 1985 | 1,600,000 |
| 1990 | 1,850,000 |
