Appendix V: Units
As described in the Units, the specification of units SHOULD follow the International System of Units (SI, abbreviated from the French Système international (d'unités)).
The CMIXF12 convention for encoding units is RECOMMENDED to achieve maximum portability and limited variability of representation. If a CMIXF12 representation of a unit is not possible, the unit can be declared as custom units and defined in an accompanying JSON file, as described in the units section. Earlier versions of the BIDS standard listed the following Unicode symbols, and these are still included for backwards compatibility:
Note that for the first two entries in this list, two characters are permissible for each, but the first character in each entry is preferred, per Unicode rules (see the section on "Duplicated Characters" on page 11 in the unicode report).
It is RECOMMENDED that units be CMIXF12 compliant or among these five Unicode characters. Please note the appropriate upper or lower casing when using CMIXF12.
For cases that are unspecified by this appendix or theunits section, the CMIXF12 convention applies.
You can use the cmixf Python package to check whether your formatting is compliant.
Examples for CMIXF12 (including the five unicode symbols mentioned above):

Different formatting of "micro Volts":
 RECOMMENDED:
uV
orµV
 NOT RECOMMENDED:
microV
,µvolt
or1e6V
 RECOMMENDED:

Combinations of units:
 RECOMMENDED:
V/us
for the Slew rate  NOT RECOMMENDED:
volts per microsecond
 RECOMMENDED:
Unit table
Unit name  Unit symbol  Quantity name 

metre  m  length 
kilogram  kg  mass 
litre (liter)  L  volume 
second  s  time 
ampere  A  electric current 
kelvin  K  thermodynamic temperature 
mole  mol  amount of substance 
candela  cd  luminous intensity 
radian  rad  angle 
steradian  sr  solid angle 
hertz  Hz  frequency 
newton  N  force, weight 
pascal  Pa  pressure, stress 
joule  J  energy, work, heat 
watt  W  power, radiant flux 
coulomb  C  electric charge or quantity of electricity 
volt  V  voltage (electrical potential), emf 
farad  F  capacitance 
ohm  Ohm  resistance, impedance, reactance 
siemens  S  electrical conductance 
weber  Wb  magnetic flux 
tesla  T  magnetic flux density 
henry  H  inductance 
degree Celsius  oC  temperature relative to 273.15 K 
lumen  lm  luminous flux 
lux  lx  illuminance 
becquerel  Bq  radioactivity (decays per unit time) 
gray  Gy  absorbed dose (of ionizing radiation) 
sievert  Sv  equivalent dose (of ionizing radiation) 
katal  kat  catalytic activity 
Prefixes
Multiples
Prefix name  Prefix symbol  Factor 

deca  da  10^{1} 
hecto  h  10^{2} 
kilo  k  10^{3} 
mega  M  10^{6} 
giga  G  10^{9} 
tera  T  10^{12} 
peta  P  10^{15} 
exa  E  10^{18} 
zetta  Z  10^{21} 
yotta  Y  10^{24} 
Submultiples
Prefix name  Prefix symbol  Factor 

deci  d  10^{1} 
centi  c  10^{2} 
milli  m  10^{3} 
micro  u  10^{6} 
nano  n  10^{9} 
pico  p  10^{12} 
femto  f  10^{15} 
atto  a  10^{18} 
zepto  z  10^{21} 
yocto  y  10^{24} 