Metric and British Units 

One of the principal advantages of the Metric System is its use of only one unit (standard of size) for each parameter (thing that is being measured). The metric units are interrelated in such a way that only five fundamental standards are necessary. These fundamental standards are identified with an * in the tables below.

MECHANICS
Parameter:Metric UnitBritish Units
time
duration, delay
second *
s
second, minute
hour, day
frequencyhertz
1/s
cycle per second
length
distance, displacement
meter
1/299 792 458 light sec
m
inch, foot, yard
rod, chain, furlong, mile
velocity, speed
rate of change of position
meter per second
m/s
foot per second
mile per hour, knot
acceleration
rate of change of velocity
meter per second squared
m/s2
foot per second squared
mass
quantity of material
kilogram *
kg
ounce, pound, slug, ton
force
push, pull, or weight
newton
kg m/s2
pound-force
impulse
force times time
newton second
kg m/s
pound-force second
momentum
mass times velocity
kilogram meter per second
kg m/s
pound foot per second
work, energy
force times distance
joule (pronounced "jewel")
= one newton meter
kg m2/s2
foot pound-force
power
rate of doing work
watt
= one joule per second
kg m2/s3
foot pound-force per second
horsepower
area
size of a surface
square meter
m2
square foot, square yard
acre, square mile
pressure
force per unit area
pascal
newton per square meter
kg/m s2
pound-force per square inch
volume, capacitycubic meter (stere)
m3
pint, quart, gallon
cubic foot, cubic yard
density, heavinessgrams per cubic centimeter
g/cm3
pounds per cubic foot

HEAT
Parameter:Metric Heat UnitBritish Heat Unit
heat energyjoule,   j
calorie, Calorie
1 cal = 4.186 joules
1 Cal = 4186 joules
British Thermal Unit, BTU
temperature changekelvins, K    * Fahrenheit degree,   F
temperaturekelvins, K degrees Fahrenheit, F

LIGHT
Parameter:Metric Light Unit
luminous intensitycandle *
luminous fluxlumen
one candle produces 4 pi lumens
illuminationlux
lumen per square meter
focusdiopter
reciprocal meters
astronomical distanceparsec

ELECTRICITY & MAGNETISM (There are no British electrical units)
Parameter:Metric Electrical Unit
electric chargecoulomb *
96,500 coul = 1 faraday
faraday = 1 mole of electrons
electromotive force (EMF)volt (joule per coulomb)
capacitancefarad (coulomb per volt)
electric currentampere (coulomb per second)
electric energyjoule (watt second)
(newton meter)
KWH = 3,600,000 joules
electric powerwatt (joule per second)
electrical resistanceohm
(volt per ampere)
electrical conductivitysiemens (coulomb per joule)
(ampere per volt)
electrical field strengthvolts per meter
electromagnetic inductancehenry (pl. henrys)
magnetic field intensityoersted (formerly the gauss)
magnetic fluxweber (108 maxwells)
magnetic flux densitytesla
weber per square meter
magnetomotive forcegilbert

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Updated July 15, 2009
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