In 1974 the current format of factory stamp was adopted.The date included is the year of introduction of the design, not the date of manufacture.

1867 – 67 or A 1868 – 68 or B 1869 – 69 or C 1870 – 70 or D 1871 – 71 or E 1872 – 72 or G 1873 – 73 or H 1874 – 74 or I 1875 – 75 or K 1876 – 76 or L 1877 – 77 or M 1878 – N 1879 – P 1880 – R 1881 – S 1882 – T 1883 – U 1884 – V 1885 – W 1886 – X 1887 – Y 1888 – Z 1889 – O 1890 – a 1892 – 1 dot on left of crown.

1893 – 1 dot each side of crown 1894 – 2 dots left 1 right 1895 – 2 dots left 2 right 1896 – 3 dots left 2 right 1897 – 3 dots left 3 right 1898 – 4 dots left 3 right 1899 – 4 dots left 4 right 1900 – 5 dots left 4 right 1901 – 5 dots left 5 right 1902 – 6 dots left 5 right 1903 – 6 dots left 6 right 1904 – plus 1 dot under circle 1905 – plus 2 dots under circle 1906 – plus 3 dots under circle 1907 – plus 4 dots under circle 1908 – plus 5 dots under circle 1909 – plus 6 dots under circle 1910 – plus 7 dots under circle 1911 – plus 8 dots under circle 1912 – plus 9 dots under circle 1913 – plus 10 dots under circle 1914 – plus 11 dots under circle 1915 – plus 12 dots under circle This dating system continued until 1915 when 24 dots are arranged around the standard printed mark.

Note: There was no ‘F’, ‘J’, or ‘Q’ used and the ‘O’ comes after the ‘Z’ in 1889.

In 1891 the mark changed, No date code was used but ‘Royal Worcester England’ appeared around the circle.

From 1928 all tableware patterns were prefixed with a ‘Z’ which continued until after 1962.