Why do Chinese patent application numbers have different lengths?

Answer:

Since the Patent Law took effect in 1985, the application-number format has passed through three main stages.

1. Filing dates in 1985–1988

The number has eight digits. The first two indicate the filing year, the third indicates the application type—1 for invention, 2 for utility model and 3 for design—and the final five form the serial number. In the following examples, 88 means 1988.

Examples: 88100001; 88210369; 88300457.

2. Filing dates from 1989 to September 30, 2003

The eight-digit format remains, with a check digit added after a decimal point. The check digit is calculated from the other digits.

Examples: 89100002.X; 89200001.5; 89300001.9.

China’s accession to the Patent Cooperation Treaty (PCT) in 1994 introduced further changes for international applications entering the Chinese national phase.

For PCT applications filed in 1994–1997, the meanings of the first three digits remain as above, but the fourth digit is 9 or 8, indicating the PCT route. Digits five to eight form the serial number, followed by a check digit.

Format examples: 94190008.8; 94180555.7; 94290001.4.

For PCT applications filed from 1998 to September 30, 2003, the first two digits indicate the filing year. The third digit is 8 for an invention application or 9 for a utility model application entering the Chinese national phase under the PCT. The next five digits form the serial number, followed by a check digit.

Examples: 98805245.8; 98900001.X.

3. Filing dates from October 1, 2003

The application number contains 12 digits followed by a decimal point and a check digit. The first four indicate the filing year. The fifth is 1 for invention, 2 for utility model or 3 for design; 8 and 9 indicate PCT national-phase invention and utility model applications respectively. The remaining seven digits form the serial number.

Examples: 200520141950.2; 200610045875.9; 200730155424.6; 201080000946.8; 201190000001.6.