The purpose of this guide is to help people date items that they think are old.

If you have a patent number on an item, you can approximately date it using the chart below, for items with a US Patent number. Patents are issued in the US every Tuesday. Each issued US Patent has a number, and the numbers are issued seriaqlly. Below is the year of the of the first patent number. By looking at the patent number and figuring out what years it was patented one can date an antique. Although this is not a Surefire method for dating items it gives a good approximation.  Furthermore, you can tell by the Term of the patent, what year range your item is from.

For example, if you have an antique widget that has stamped on it "Patented U.S. Patent 1,241,111 and other patents pending" you can look at the chart below and determine that the earliest date of the item would be about 1917-1918, and had a term from 1917 to 1934 (17 Years), so that is the approximate window of time of your widget.

Utility and Plant Patents Term

1790-1836: 14 years
1836-1861: 14 years + 7 year extension
1861-1995: 17 years
1995-present: 20 years from filing

Design Patents Term

1842-1861: 7 years
1861-1981: 3½, 7 or 14 years
1981-present: 14 years

Utility Patent Numbers

Utility patents cover new processes, machines, manufactured articles, and chemical compositions.

Date...Patent Number

US Design Patent Numbers

Design patents cover new ornamental designs for manufactured articles. They usually begin with a "D"

YEAR Patent Number

1843  D1
1844  D15
1845  D27
1846  D44
1847  D103
1848  D163
1849  D209
1850  D258
1851  D341
1852  D431
1853  D540
1854  D626
1855  D683
1856  D753
1857  D860
1858  D973
1859  D1,075
1860  D1,183
1861  D1,366
1862  D1,508
1863  D1,703
1864  D1,879
1865  D2,018
1866  D2,239
1867  D2,553
1868  D2,858
1869  D3,304
1870  D3,810
1871  D4,547
1872  D5,452
1873  D6,336
1874  D7,083
1875  D7,969
1876  D8,884
1877  D9,686
1878  D10,385
1879  D10,975
1880  D11,567
1881  D12,082
1882  D12,647
1883  D13,508
1884  D14,528
1885  D15,678
1886  D16,541
1887  D17,046
1888  D17,995
1889  D18,830
1890  D19,553
1891  D20,439
1892  D21,275
1893  D22,092
1894  D22,994
1895  D23,922
1896  D25,037
1897  D26,482
1898  D28,113
1899  D29,916
1900  D32,055
1901  D33,813
1902  D35,547
1903  D36,198
1904  D36,723
1905  D37,280
1906  D37,766
1907  D38,391
1908  D38,980
1909  D39,737
1910  D40,424
1911  D41,063
1912  D43,073
1913  D43,415
1914  D45,098
1915  D46,813
1916  D48,358
1917  D50,117
1918  D51,629
1919  D52,836
1920  D54,359
1921  D56,844
1922  D60,121
1923  D61,748
1924  D63,675
1925  D66,346
1926  D69,170
1927  D71,772
1928  D74,159
1929  D7,347
1930  D80,254
1931  D82,966
1932  D85,903
1933  D88,847
1934  D91,258
1935  D94,179
1936  D98,045
1937  D102,601
1938  D107,738
1939  D112,765
1940  D118,358
1941  D124,503
1942  D130,989
1943  D134,717
1944  D136,946
1945  D139,862
1946  D143,386
1947  D146,165
1948  D148,267
1949  D152,235
1950  D156,686
1951  D161,404
1952  D165,568
1953  D168,527
1954  D171,241
1955  D173,777
1956  D176,490
1957  D179,467
1958  D181,829
1959  D184,204
1960  D186,973
1961  D189,516
1962  D192,004
1963  D194,304
1964  D197,269
1965  D199,955
1966  D203,379
1967  D206,567
1968  D209,732
1969  D213,084
1970  D216,469
1971  D219,637
1972  D222,793
1973  D225,695
1974  D229,729
1975  D234,033
1976  D238,315
1977  D242,881
1978  D246,811
1979  D250,676
1980  D253,796
1981  D257,746
1982  D262,495
1983  D268,440
1984  D272,009
1985  D276,949
1986  D282,020
1987  D287,540
1988  D293,500
1989  D299,180
1990  D305,275
1991  D313,301
1992  D322,878
1993  D332,170
1994  D342,818
1995  D353,932
1996  D365,671
1997  D377,107
1998  D388,585
1999  D403,485
2000  D418,273