Note 1.J Units of the Systeme Internationale
measure name of unit value conversion to SI units
length meter (m) base unit 1 inch = 0.025 4m
micrometer (mm) 10-6 m 1 foot = 0.304 8m
10-3 m 1 yard= 0.914 4m
103 m 1 mile= 1,609m
millimeter (mm)
kilometer (km)
mass kilogram (kg) base unit 1 ounce avoirdupois = 28.35g*
milligram (mg) 10-6 kg 1 pound = 0.453 6kg
gram (g) 10-3 kg 1 stone = 6.350kg
103 kg 1 hundredweight = 50.80kg
tonne (t) 1 US ton = 907.2kg
1 ton = 1,016kg
time second (s) base unit
minute (min) 60s
hour (h) 3,600s
day (d) 86,400s
year (a) 365.25 days
area square metre (m2) SI unit 1 square inch = 6.452cm2*
square centimetre (cm2) 10-4 m2 1 square foot = 0.092 90m2
hectare (ha) 104 m2 1 square yard = 0.836 1m2
square kilometre (km2) 106 m2 1 acre = 0.404 7ha*
1 square mile = 2.590km2*
volume cubic metre (m3) SI unit 1 cubic inch = 16.39cm3*
cubic centimetre (cm3) 10-6 m3 1 cubic foot = 0.028 32m3
litre (L) 10-3 m3 1 cubic yard = 0.764 6m3
10-6 m3 1 fluid ounce = 28.41mL*
103 m3 1 British pint = 0.568 3L*
millilitre (mL) 1 British gallon = 4.546L*
megalitre (ML) 1 bushel = 36.37L*
1 acre foot = 1.233ML*
velocity metre per second (m/s) SI unit 1 foot per second = 0.304
kilometre per hour (km/h) 0.277 7m/s 8m/s
1 mile per hour = 0.447 0m/s
1 knot = 0.514 4m/s
= 1.852km/h*
= 1 minute of latitude on
Earth per hour
1 km/h = 0.277 8m/s
1 inch per year = 25.40mm/a
energy joule (J), i.e. 1 kg.m2/s3 SI unit 1 calorie# = 4.187J
kilojoule (kJ) 103 J 1 kilocalorie# = 4187J
megajoule (MJ) 106 J 1 British thermal unit =
1.055kJ*
1kWh = 3.600MJ*
power watt (W), i.e. 1 J/s, or 1 SI unit 1 calorie per minute =
kg.m2/s3 10-3 W 69.78W*
milliwatt (mW) 103 W 1 calorie per second =
kilowatt (kW) 106 W 4.187W*
megawatt (MW) 1 horsepower = 0.745 7kW*
energy watt per square metre (W/m2), SI unit 1 calorie per square
density i.e. centimetre day
flux 1 kg/s3 10W/m2 = 0.484 6W/m2
milliwatt per square 1 kilocalorie per square
centimetre centimetre year = 1.328W/m2
(mW/cm2) 1 langley/min = 697.8W/m2
density kilogram per cubic metre SI unit 1 pound per cubic inch=
(kg/m3) 10-3 kg/m3 27.70g/cm3= 27.79t/m3
gram per cubic metre (g/m3) 103 kg/m3 1 pound per cubic foot =
gram per cubic centimetre 103 kg/m3 16.02kg/m3
(g/cm3)
tonne per cubic metre (t/m3)
force newton (N), i.e. 1 kg.m/s2 SI unit 1 dyne = 10-4N
kilonewton (kN) 103 N 1 pound force = 4.448N
meganewton (MN) 106 N 1 poundal = 9.964kN
1 ton force = 9.964kN
pressure pascal (Pa) i.e. 1 kg/m.s2 SI unit 1 millibar = 1 hectopascal =
and (N/m2) 100Pa
stress 100Pa 1 bar = 100 000Pa
1 pound force per square foot
= 47.88Pa
1 pound force per square inch
= 6.897 kPa
1 inch mercury = 3.386kPa
1 millimetre mercury =
133.3Pa
1 atmosphere = 101.3kPa
temperatu kelvin (K) base unit °C = 5 (°F - 32) / 9
re degree Celsius (°C) K - 273.155
angle radian (rad) SI unit 100 degrees = 1.745rad
milliradian (mrad) 10 -3 rad 1 degree of latitude on Earth
degree (...°) = 111.1km
minute (...') 1/60 degree 1 degree per hour
second (...") 1/60 = 4.847 x 10-6rad/s
minuite
*Not base SI units but derived from them. # A human being eats about 2500 kilocalories per day, not 2500 calories. This is a common confusion.