Resolution 12 of the 11th CGPM (1960)

Système International d'Unités

The 11th Conférence Générale des Poids et Mesures (CGPM),



  1. the system founded on the six base units above is called the "Système International d'Unités";
  2. the international abbreviation of the name of the system is SI;
  3. names of multiples and submultiples of the units are formed by means of the following prefixes:


    Multiplying factor Prefix Symbol
    1 000 000 000 000 = 1012 tera T
    1 000 000 000 = 109 giga G
    1 000 000 = 106 mega M
    1 000 = 103 kilo k
    100 = 102 hecto h
    10 = 101 deca da
    Multiplying factor Prefix Symbol
    0.1 = 10–1 deci d
    0.01 = 10–2 centi c
    0.001 = 10–3 milli m
    0.000 001 = 10–6 micro µ
    0.000 000 001 = 10–9 nano n
    0.000 000 000 001 = 10–12 pico p
  4. the units listed below are used in the system, without excluding others which might be added later.

Supplementary units

Plane angle radian rad
Solid angle steradian sr


Derived units

area square metre m2  
volume cubic metre m3  
frequency hertz Hz 1/s
mass density (density) kilogram per cubic metre kg/m3  
speed, velocity metre per second m/s  
angular velocity radian per second rad/s  
acceleration metre per second squared m/s2  
angular acceleration radian per second squared rad/s2  
force newton N kg · m/s2
pressure (mechanical stress) newton per square metre N/m2  
kinematic viscosity square metre per second m2/s  
dynamic viscosity newton-second per square metre N · s/m2  
work, energy, quantity of heat joule J N · m
power watt W J/s
quantity of electricity coulomb C A · s
tension (voltage), difference, electromotive force volt V W/A
electric field strength volt per metre V/m  
electric resistance ohm Ω V/A
capacitance farad F A · s/V
magnetic flux weber Wb V · s
inductance henry H V · s/A
magnetic flux density tesla T Wb/m2
magnetic field strength ampere per metre A/m  
magnetomotive force ampere A  
luminous flux lumen lm cd · sr
luminance candela per square metre cd/m2  
illuminance lux lx lm/m2

DOI : 10.59161/CGPM1960RES12E

The reader should note that the official version of this Resolution is the French text


The CGPM later abrogated certain of its decisions and extended the list of prefixes:

  • The name and symbol for the unit of thermodynamic temperature were modified by the 13th CGPM in 1967 (Resolution 3).
  • A seventh base unit, the mole, was adopted by the 14th CGPM in 1971 (Resolution 3).
  • Further prefixes were adopted by the 12th CGPM in 1964 (Resolution 8), the 15th CGPM in 1975 (Resolution 10), and the 19th CGPM in 1991 (Resolution 4).
  • The 20th CGPM in 1995 abrogated the class of supplementary units in the SI (Resolution 8). These are now considered as derived units.
  • The 13th CGPM in 1967 (Resolution 6) specified other units which should be added to this list of derived units. In principle, the list is without limit.
  • Modern practice is to use the phrase "amount of heat" rather than "quantity of heat", because the word quantity has a different meaning in metrology.
  • Modern practice is to use the phrase "amount of electricity" rather than "quantity of electrcity" (see above).

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