Weights and Measures Act (R.S.C., 1985, c. W-6)

Act current to 2014-06-12 and last amended on 2011-11-29. Previous Versions

SCHEDULE I(Section 4)UNITS BASED ON THE INTERNATIONAL SYSTEM OF UNITS

PART I
BASIC UNITS OF MEASUREMENT

Basic UnitSymbolDefinition
1.metremthe unit for the measurement of length, being a length equal to the distance travelled by light in a vacuum during 1/299 792 458 of a second
2.kilogramkgthe unit for the measurement of mass, being a mass equal to the mass of the international prototype of the kilogram established in the year 1889 by the First General Conference of Weights and Measures and deposited at the International Bureau of Weights and Measures
3.secondsthe unit for the measurement of time, being the 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
4.ampereAthe unit for the measurement of electric current, being a constant current that, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section and placed one metre apart in vacuum, would produce between those conductors a force equal to 2 x 10-7newton per metre of length
5.kelvinKthe unit for the measurement of thermodynamic temperature, being the fraction 1/273.16 of the thermodynamic temperature of the triple point of water
6.candelacdthe unit for the measurement of luminous intensity, being the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian
7.molemolthe unit for the measurement of the amount of substance, being the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12

PART II
SUPPLEMENTARY UNITS OF MEASUREMENT

Supplementary UnitSymbolDefinition
1.radianradthe unit for the measurement of a plane angle, being the angle with its vertex at the centre of a circle and subtended by an arc of the circle that is equal in length to its radius
2.steradiansrthe unit for the measurement of a solid angle, being the angle with its vertex at the centre of a sphere and subtended by an area on the spherical surface equal to that of a square with sides equal in length to the radius

PART III
DERIVED UNITS OF MEASUREMENT

Derived UnitSymbolDefinition
1.newtonNthe force that, when applied to a body having a mass of one kilogram, gives the body an acceleration of one metre per second per second
2.jouleJthe work done when the point of application of a force of one newton is displaced a distance of one metre in the direction of the force
3.wattWthe power that produces energy at the rate of one joule per second
4.hertzHzthe frequency of a periodic phenomenon of which the periodic time is one second
5.coulombCthe quantity of electricity transported in one second by a current of one ampere
6.voltVthe unit of electric potential difference and electromotive force, being the difference of electric potential between two equipotential surfaces of a conductor that is carrying a constant current of one ampere when the power dissipated between these surfaces is equal to one watt
7.faradFthe capacitance of a capacitor between the equipotential surfaces of which there appears a difference of potential of one volt when the capacitor is charged by a quantity of electricity equal to one coulomb
8.henryHthe inductance of a closed circuit in which an electromotive force of one volt is produced when the electric current in the circuit varies uniformly at a rate of one ampere per second
9.ohmthe electric resistance between two points of a conductor when a constant difference of potential of one volt, applied between these two points, produces in the conductor a current of one ampere and the conductor itself is not the seat of any electromotive force
10.weberWbthe magnetic flux that, when linking a circuit of one turn, produces in that circuit an electromotive force of one volt as the flux is reduced to zero at a uniform rate in one second
11.teslaTthe magnetic induction that is equal to one weber per square metre
12.lumenlmthe luminous flux emitted in a solid angle of one steradian by a point source having an intensity of one candela
13.luxlxthe illuminance produced by a flux of one lumen uniformly distributed over one square metre
14.pascalPathe pressure (or stress) produced when a force of one newton is applied to an area of one square metre
15.varvarthe reactive power at the two points of entry of a single-phase, two-wire circuit when the product of the root-mean-square value in amperes of the sinusoidal current by the root-mean-square value in volts of the sinusoidal voltage and by the sine of the angular phase difference by which the voltage leads the current is equal to one
16.becquerelBqthe activity of radionuclides that is equal to one per second
17.grayGythe absorbed dose of ionizing radiation that is equal to one joule per kilogram
18.siemensSthe electric conductance between two points of a conductor when a constant current of one ampere in the conductor produces a difference of potential of one volt between these two points and the conductor itself is not the seat of any electromotive force

PART IV
CUSTOMARY UNITS OF MEASUREMENT USED WITH THE INTERNATIONAL SYSTEM

Customary UnitSymbolDefinition
minutemin60 seconds
hourh3 600 seconds
dayd86 400 seconds
degree (of arc)°p/180 radianFootnote for *
minute (of arc)p/10 800 radianFootnote for *
second (of arc)p/648 000 radianFootnote for *
litreL, l or l1/1 000 cubic metre
tonne or metric tont1 000 kilograms
hectareha104 square metres
millilitremL, ml or ml1/1 000 litre
degree Celsius°Can interval of 1°C = an interval of 1 kelvin; a temperature of 0°C corresponds to 273.15 kelvins

PART V
PREFIXESFootnote * FOR MULTIPLES AND SUBMULTIPLES OF BASIC, SUPPLEMENTARY AND DERIVED UNITS OF MEASUREMENT

PrefixSymbolDefinition
yottaY1024
zettaZ1021
exaE1018
petaP1015
teraT1012
gigaG109
megaM106
kilok103
hectoh102
decada101
decid10-1
centic10-2
millim10-3
microµ10-6
nanon10-9
picop10-12
femtof10-15
attoa10-18
zeptoz10-21
yoctoy10-24
  • Return to footnote *Not applicable to the basic unit “kilogram” but applicable to the one thousandth submultiple of that unit, namely the “gram (g)”.

  • R.S., 1985, c. W-6, Sch. I;
  • SOR/86-420;
  • SOR/2005-277, ss. 1, 2.