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SI(Modern Metric) Conversion Factors


SI (MODERN METRIC) CONVERSION FACTORS

APPROXIMATE CONVERSIONS TO SI UNITS

APPROXIMATE CONVERSIONS FROM SI UNITS

Symbol

When You Know

Multiply By

To Find

Symbol

Symbol

When You Know

Multiply By

To Find

Symbol


LENGTH


LENGTH

in inches 25.4 millimeters mm mm millimeters 0.039 inches in
ft feet 0.305 meters m m meters 3.28 feet ft
yd yards 0.914 meters m m meters 1.09 yards yd
mi miles 1.61 kilometers km km kilometers 0.621 miles mi

AREA


AREA

in2 square inches 645.2 square millimeters mm2 mm2 square millimeters 0.0016 square inches in2
ft2 square feet 0.093 square meters m2 m2 square meters 10.764 square feet ft2
yd2 square yards 0.836 square meters m2 m2 square meters 1.195 square yards ac
ac acres 0.405 hectares ha ha hectares 2.47 acres mi2
mi2 square miles 2.59 square kilometers km2 km2 square kilometers 0.386 square miles  

VOLUME


VOLUME

fl oz fluid ounces 29.57 milliliters ml ml milliliters 0.034 fluid ounces fl oz
gal gallons 3.785 liters l l liters 0.264 gallons gal
ft3 cubic feet 0.028 cubic meters m3 m3 cubic meters 35.71 cubic feet ft3
yd3 cubic yards 0.765 cubic meters m3 m3 cubic meters 1.307 cubic yard yd3
NOTE: Volumes greater than 1000 l shall be shown in m3

MASS


MASS

oz ounces 28.35 grams g g grams 0.035 ounces oz
lb pounds 0.454 kilograms kg kg kilograms 2.202 pounds lb
T short tons (2000 lb) 0.907 megagrams Mg Mg megagrams 1.103 short tons (2000 lb) T

TEMPERATURE (exact)


TEMPERATURE (exact)

°F Fahrenheit temperature 5(F-32)/9 or (F-32)/1.8 Celcius temperature °C °C Celcius temperature 1.8C +32 Fahrenheit temperature °F

ILLUMINATION


ILLUMINATION

fc foot-candles 10.76 lux l lx lux 0.0929 foot-candles fc
fl foot-Lamberts 3.426 candela/m2 cd/m2 cd/m2 candela/m2 0.2919 foot-Lamberts fl

FORCE and PRESSURE or STRESS


FORCE and PRESSURE or STRESS

lbg poundforce 4.45 newtons N N newtons 0.225 poundforce lbf
psi poundforce per square inch 6.89 kilopascals kPa kPa kilopascals 0.145 poundforce per square inch psi
(Revised August 1992)

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

in2 square inches 645.2 square millimeters mm2
ft2 square feet 0.093 square meters m2
yd2 square yards 0.836 square meters m2
ac acres 0.405 hectares ha
mi2 square miles 2.59 square kilometers km2

VOLUME

fl oz fluid ounces 29.57 milliliters ml
gal gallons 3.785 liters l
ft3 cubic feet 0.028 cubic meters m3
yd3 cubic yards 0.765 cubic meters m3
NOTE: Volumes greater than 1000 l shall be shown in m3

MASS

oz ounces 28.35 grams g
lb pounds 0.454 kilograms kg
T short tons (2000 lb) 0.907 megagrams Mg

TEMPERATURE (exact)

°F Fahrenheit temperature 5(F-32)/9 or (F-32)/1.8 Celcius temperature °C

ILLUMINATION

fc foot-candles 10.76 lux l
fl foot-Lamberts 3.426 candela/m2 cd/m2

FORCE and PRESSURE or STRESS

lbg poundforce 4.45 newtons N
psi poundforce per square inch 6.89 kilopascals kPa
(Revised August 1992)

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

mm2 square millimeters 0.0016 square inches in2
m2 square meters 10.764 square feet ft2
m2 square meters 1.195 square yards ac
ha hectares 2.47 acres mi2
km2 square kilometers 0.386 square miles  

VOLUME

ml milliliters 0.034 fluid ounces fl oz
l liters 0.264 gallons gal
m3 cubic meters 35.71 cubic feet ft3
m3 cubic meters 1.307 cubic yard yd3
NOTE: Volumes greater than 1000 l shall be shown in m3

MASS

g grams 0.035 ounces oz
kg kilograms 2.202 pounds lb
Mg megagrams 1.103 short tons (2000 lb) T

TEMPERATURE (exact)

°C Celcius temperature 1.8C +32 Fahrenheit temperature °F

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 poundforce lbf
kPa kilopascals 0.145 poundforce per square inch psi
(Revised August 1992)

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

The use of SI units is encouraged with Part VI. Future editions of Part VI will use only SI units. The conversions will be based primarily on AASHTO guides. Specific conversion of standards will be subjected to the FEDERAL REGISTER rulemaking process.

U.S. Department of Transportation
Federal Highway Administration

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