SI* (Modern Metric) Conversion Factors
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
yard 
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}

cubic
feet 
0.028 
cubic
meters 
m^{3} 
yd^{3}

cubic
yards 
0.765 
cubic
meters 
m^{3} 
NOTE: volumes greater than 1000 L shall
be shown in m^{3}

MASS

oz

ounces 
28.35 
grams 
g 
lb

pounds 
0.454 
kilograms 
kg 
T

short tons
(2000 lb) 
0.907 
megagrams
(or "metric ton") 
Mg (or
"t") 
TEMPERATURE
(exact degrees) 
^{o}F

Fahrenheit 
5 (F32)/9
or (F32)/1.8

Celsius 
^{o}C 
ILLUMINATION

fc

footcandles 
10.76 
lux 
lx 
fl

footLamberts 
3.426 
candela/m^{2} 
cd/m^{2} 
FORCE and PRESSURE or STRESS

lbf

poundforce 
4.45 
newtons 
N 
lbf/in^{2}

poundforce
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 
in^{2} 
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 
35.314

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 (or "t")

megagrams
(or "metric ton") 
1.103

short
tons (2000 lb) 
T 
TEMPERATURE (exact degrees)

^{o}C

Celsius 
1.8C+32 
Fahrenheit 
^{o}F 
ILLUMINATION

lx

lux 
0.0929

footcandles 
fc 
cd/m^{2}

candela/m^{2} 
0.2919

footLamberts 
fl 
FORCE and PRESSURE or STRESS

N

newtons 
0.225 
poundforce 
lbf 
kPa

kilopascals 
0.145

poundforce per square inch 
lbf/in^{2} 
*SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003)