Search facility:  
BIPM Home | Site map | Metrologia | KCDB | JCTLM-DB | Contact us  
Non-SI units accepted for use with the SI, and units based on fundamental constants
Version française
Non-SI units accepted for use with the SI, and units based on fundamental constants
Other non-SI units not recommended for use

Search the SI brochure
Direct access

SI brochure, Table 9 (Section 4.1)

Table 9. Non-SI units associated with the CGS and the CGS-Gaussian system of units

Quantity Name of unit Symbol for unit Value in SI units
energy erg (a) erg 1 erg = 10–7 J
force dyne (a) dyn 1 dyn = 10–5 N
dynamic viscosity poise (a) P 1 P = 1 dyn s cm–2 = 0.1 Pa s
kinematic viscosity stokes St 1 St = 1 cm2 s–1 = 10–4 m2 s–1
luminance stilb (a) sb 1 sb = 1 cd cm–2 = 104 cd m–2
illuminance phot ph 1 ph = 1 cd sr cm–2 = 104 lx
acceleration gal (b) Gal 1 Gal = 1 cm s–2 = 10–2 m s–2
magnetic flux maxwell (c) Mx 1 Mx = 1 G cm2 = 10–8 Wb
magnetic flux density gauss (c) G 1 G = 1 Mx cm–2 = 10–4 T
magnetic field œrsted (c) Oe 1 Oe corresponds to (103/4pi) A m–1

(a) This unit and its symbol were included in Resolution 7 of the 9th CGPM (1948).
(b) The gal is a special unit of acceleration employed in geodesy and geophysics to express acceleration due to gravity.
(c) These units are part of the so-called "electromagnetic" three-dimensional CGS system based on unrationalized quantity equations, and must be compared with care to the corresponding unit of the International System which is based on rationalized equations involving four dimensions and four quantities for electromagnetic theory. The magnetic flux, phi, and the magnetic flux density, B, are defined by similar equations in the CGS system and the SI, so that the corresponding units can be related as in the table. However, the unrationalized magnetic field, H (unrationalized) = 4pi x H (rationalized). The equivalence symbol corresponds to is used to indicate that when H (unrationalized) = 1 Oe, H (rationalized) = (103/4pi) A m–1.

Note: For the official text, please refer to the PDF files available at:
  • (in English) and
  • (in French).