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METRIC AND INTERNATIONAL MEASUREMENT

METRIC AND OTHER INTERNATIONAL UNITS OF MEASUREMENT

NATIONAL GEOGRAPHIC uses standard measurements except in natural history and science articles where metric, if appropriate, may be substituted.

Supplement maps generally use standard measurements with metric in parentheses.

Weight and measures may be abbreviated in credit lines and map notes. Such abbreviations do not take periods; plurals do not add s or es:
            vase 12 cm, 16 mm, f/22, 11 sq mi, three hr, 8-in snake, 11 min 30 sec, 49-yr span.


International Units of Measurement

Quantity
U.S. Units
Symbol
Acceptable Equivalent
Symbol

length


kilometer
meter
centimeter
millimeter
micrometer


km
m
cm
mm
µm


 


 

area


square kilometer
square hectometer
square meter
square centimeter
square millimeter


km2
km2
m2
cm2
mm2



hectare



ha

volume


cubic meter
cubic decimeter
cubic centimeter
cubic millimeter


m3
dm3
cm3
mm3


 


 

liquid volume*


liter
milliliter
microliter


L
mL
µL


 


 

speed or velocity


meters per second
kilometers per hour


m/s
km/h


 


 

acceleration


meters per sec ond squared


m/s2


 


 

frequency


megahertz
kilohertz
hertz


MHz
kHz
Hz


 


 

mass


megagram
kilogram
gram
milligram


Mg
kg
g
mg


metric ton


 

density


kilogram per cubic meter


kg/m3


gram per liter


g/L

force


kilonewton
newton


kN
N


 


 

pressure


kilopascal


kPa


 


 

energy, work or
quantity of heat


megajoule
kilojoule
joule
kilowatt-hour**


MJ
kJ
J
kWh


 


 

power or heat flow rate


kilowatt
watt


kW
W


 


 

temperature


kelvin
degrees Celsius


K
°C


 


 

electric current


ampere


A


 


 

quantity of electricity


coloumb
ampere-hour


C
A-h


 


 

electromotive force


volt


V


 


 

electric resistance


ohm


W


 


 

luminous intensity


candela


cd


 


 

* To be used only for fluids (both gases and liquids) and for wet ingredients in recipes.
** Note abbreviations for kilowatt-hour (kWh), megawatt-hour (MWh), gigawatt-hour (GWh), terawatt-hour (TWh).



Conversion of U.S. units of measurement to international units

Quantity
If you know   Multiply by   To find

length


inches
feet
yards
miles

X
X
X
X

25.400
0.305
0.914
1.609

=
=
=
=

millimeters
meters
meters
kilometers

area


square yards
acres

X
X

0.836
0.405

=
=

square meters
hectares

volume


quarts (lq)
cubic yards

X
X

0.946
0.765

=
=

liters
cubic meters

liquid volume


quarts

X

0.946

=

liters

mass


ounces (avdp)
pounds (avdp)

X
X

28.350
0.454

=
=

grams
kilograms

temperature


degrees Farenheit

 

subtract 32
then multiply by 5/9


=

degrees Celsius



Conversion of international units to U.S. units of measurement

Quantity
If you know   Multiply by   To find

length


millimeters
meters
meters
kilometers

X
X
X
X

0.039
3.281
1.094
0.621

=
=
=
=

inches
feet
yards
miles

area


square meters
hectares

X
X

1.196
2.471

=
=

square yards
acres

volume


liters
cubic meters

X
X

1.057
1.308

=
=

quarts (lq)
cubic yards

mass


grams
kilograms

X
X

0.035
2.205

=
=

ounces (avdp)
pounds (avdp)

temperature


degrees Celsius



multiply by 9/5
then add 32

=

degrees Farenheit



See also kilometer, kmmeter, m, centimeter, cm, cubic centimeter, ccmillimeter, mm