| 1st (1889) | kilogram defined as mass of the international prototype kilogram (IPK) made of platinum-iridium and kept at the International Bureau of Weights and Measures (Bureau international des poids et mesures), Sèvres, France. International prototype metre sanctioned. |
| 2nd (1897) | No resolutions were passed by the 2nd CGPM. |
| 3rd (1901) | litre redefined as volume of 1 kg of water. Clarified that kilograms are units of mass, "standard weight" defined, standard acceleration of gravity defined endorsing use of grams force and making them well-defined. |
| 4th (1907) | carat = 200 mg adopted. |
| 5th (1913) | International Temperature Scale proposed. |
| 6th (1921) | Metre Convention revised. |
| 7th (1927) | Consultative Committee for Electricity (CCE) created. |
| 8th (1933) | Need for absolute electrical unit identified. |
| 9th (1948) | ampere, bar, coulomb, farad, henry, joule, newton, ohm, volt, watt, weber defined. Chose degree Celsius from among the three names then in use. l (lowercase L) adopted as symbol for litre. Both the comma and dot on a line are accepted as decimal marker symbols. Symbols for the stere and second changed [1]. The universal return to the Long Scale numbering system was proposed but not adopted. |
| 10th (1954) | kelvin, standard atmosphere defined. International System of Units (metre, kilogram, second, ampere, kelvin, candela) began. |
| 11th (1960) | metre redefined in terms of wavelengths of light. Units: hertz, lumen, lux, tesla adopted. New metric system given the official symbol SI for Système International d'Unités, the "modernized metric system". Prefixes pico-, nano-, micro-, mega-, giga- and tera- confirmed. |
| 12th (1964) | original definition of litre = 1 dm³ restored. atto- and femto- prefixes. |
| 13th (1967) | second redefined as duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at a temperature of 0 K. Degree Kelvin renamed kelvin. Candela redefined. |
| 14th (1971) | new SI base unit mole defined. pascal, siemens approved. |
| 15th (1975) | peta- and exa- prefixes. gray and becquerel radiological units. |
| 16th (1979) | candela, sievert defined. Both l and L provisionally allowed as symbols for litre. |
| 17th (1983) | metre redefined in terms of the speed of light, but keeps same length. |
| 18th (1987) | conventional values adopted for Josephson constant, KJ, and von Klitzing constant, RK, preparing the way for alternative definitions of the ampere and kilogram. |
| 19th (1991) | new prefixes yocto-, zepto-, zetta- and yotta-. |
| 20th (1995) | SI supplementary units (radian and steradian) become derived units. |
| 21st (1999) | new SI derived unit, the katal = mole per second, for the expression of catalytic activity. |
| 22nd (2003) | a comma or a dot on a line are reaffirmed as decimal marker symbols, and not as grouping symbols in order to facilitate reading; "numbers may be divided in groups of three in order to facilitate reading; neither dots nor commas are ever inserted in the spaces between groups". [2]. |
| 23rd (2007) | clarification about the kelvin and thoughts about possible revision of certain base units |
