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SI* (MODERN METRIC) CONVERSION FACTORS
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APPROXIMATE CONVERSIONS TO SI UNITS

Symbol When You Know Multiply By To Find Symbol
LENGTH
In inches 25.4 millimeters mm
Ft feet 0.305 meters m
Yd yards 0.914 meters m
Mi miles 1.61 kilometers km
AREA
in 2 square inches 645.2 square millimeters mm 2
ft 2 square feet 0.093 square meters m 2
yd 2 square yards 0.836 square meters m 2
Ac acres 0.405 hectares ha
mi 2 square miles 2.59 square kilometers km 2
VOLUME
fl oz fluid ounces 29.57 milliliters ml
Gal gallons 3.785 liters l
ft 3 3 cubic feet 0.028 cubic meters m 3
yd 3 cubic yards 0.765 cubic meters m 3
MASS
Oz ounces 28.35 grams g
Lb pounds 0.454 kilograms kg
T short tons (2000 lbs) 0.907 megagrams Mg
TEMPERATURE (exact)
F Fahrenheit 5(F-32)/9 Celsius C
  temperature or (F-32)/1.8 temperature  
ILLUMINATION
Fc foot-candles 10.76 lux lx
Fl foot-Lamberts 3.426 candela/m2 cd/m2
FORCE and PRESSURE or STRESS
Lbf pound-force 4.45 newtons N
Psi pound-force per square inch 6.89 kilopascals kPa

APPROXIMATE CONVERSIONS FROM SI UNITS

Symbol When You Know Multiply By To Find Symbol
LENGTH
mm millimeters 0.039 inches in
m meters 3.28 feet ft
m meters 1.09 Yards yd
km kilometers 0.621 miles mi
AREA
mm 2 square millimeters 0.0016 square inches in2
m 2 square meters 10.764 square feet ft 2
m 2 square meters 1.195 square yards yd 2
ha hectares 2.47 acres ac
km 2 square kilometers 0.386 square miles mi 2
VOLUME
ml milliliters 0.034 fluid ounces fl oz
l liters 0.264 gallons gal
m 3 cubic meters 35.71 cubic feet ft 3
m 3 cubic meters 1.307 cubic yards yd 3
MASS
g grams 0.035 ounces oz
kg kilograms 2.202 pounds lb
Mg megagrams 1.103 short tons (2000 lbs) T
TEMPERATURE (exact)
C Celsius 1.8 C + 32 Fahrenheit F
  temperature   temperature  
ILLUMINATION
lx lux 0.0929 foot-candles fc
cd/m2 candela/m2 0.2919 foot-Lamberts fl
FORCE and PRESSURE or STRESS
N newtons 0.225 pound-force lbf
kPa kilopascals 0.145 pound-force per square inch psi

* SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380.


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