Conversion Factors
Note: Conversion factors are given here to generally three or four significant figures.
Mass
14 .59 kg
slug
Standard SI unit: kilogram (kg). Equivalent unit: N.s2/m.
Force
4.448 N
lb f
Standard SI unit: Newton (N). Equivalent unit: kg.m/s2.
32 .174 lb m
slug
2.205 lb m
kg
2000 lb m
ton m
453 .6 grams
lb m
1000 kg
metric ton m
10 5 dynes
N
4.448 x 105 dynes
lb f
224.8 lb f
kN
Length
3.281 ft
m
39.37 in
m
12 in
ft
1.609 km
mi
5280 ft
mi
Area
144 in 2
ft 2
10 .76 ft 2
m2
645 .2 mm 2
in 2
10 6 mm 2
m2
43,560 ft 2
acre
231 in 3
gal
7.48 gal
ft 3
61 .02 in 3
L
264.2 gal
m3
1000 cm 3
L
3.785 L
35 .31 ft 3
gal
m3
1.201 U.S. gal
Imperial gallon
6076 ft
nautical mile
10 4 m 2
hectare
Volume
1728 in 3
ft 3
28.32 L
ft 3
1000 L
m3
Volume Flow Rate
35 .31 ft 3 /s
449 gal/min
m 3 /s
ft 3 /s
60 000 L/min
m 3 /s
15 850 gal/min
m 3 /s
2119 ft 3 /min
m 3 /s
Density (mass/unit volume)
515.4 kg/m3
1000 kg/m3
slug/ft3
gram/cm3
3.785 L/min
gal/min
16.67 L/min
m 3 /h
101 .9 m 3 /h
ft 3 /s
32.17 lb m /ft3
slug/ft3
16.018 kg/m3
lb m /ft 3
27.674 g/cm3
lb m /in 3
Specific Weight (weight/unit volume)
1728 lb/ft 3
157.1 N/m 3
lb/in 3
lb f /ft3
General Approach to Application of Conversion Factors. Arrange the conversion factor from the table in such a manner
that, when multiplied by the given quantity, the original units cancel out, leaving the desired units.
Example 1
Convert 150 gal/min to the units of the units of m3/s:
(150 gal/min)
1 m 3 /s
= 9.46 x 10-3m3/s
15 850 gal/min
Pressure
Standard S1 unit: Pascal (Pa). Equivalent units: N/m2 or kg/m.s2.
144 lb/ft 2
14 .50 lb/in 2
47.88 Pa
6895 Pa
1 Pa
100 kPa
bar
lb/in 2
bar
lb/ft 2
lb/in 2
N/m 2
27.68 inH 2 O 249 .1 Pa 2.036 inHg 3386 Pa 133 .3 Pa
mH 2 O
51.71 mmHg
2
2
2
inH 2 O
2.896inHg
inHg
mmHg
lb/in
lb/in
lb/in
14 .696 lb/in 2
Std. atmosphere
101 .325 kPa
Std. atmosphere
29 .92 inHg
Std. atmosphere
760 .1 mmHg
Std. atmosphere
mH 2 O
1.422lb/in 2
33.9 ftH 2 O
Std. atmosphere
Note: Conversion factors based on the height of a column of liquid (e.g. inH 2O and mmHg) are based on a standard gravitational field
(g = 9.80665 m/s2), a density of water equal to 1000 kg/m3, and a density of mercury equal to 13595.1 kg/m3, sometimes called
conventional values for a temperature at or near 0oC. Actual measurements with such fluids may vary because of differences in local
gravity and temperature.
Stress
144 lb/ft 2
lb/in 2
Standard S1 unit: Pascal (Pa). Equivalent units: N/m2 or kg/m.s2.
47.88 Pa
6895 Pa
1 Pa
2
2
lb/ft
lb/in
N/m 2
Energy
1.356 J
ft.lb
Standard S1 unit: joule (J), Equivalent units: N.m or kg.m2/s2
1.0 J 8.85 lb.in
1.055 kJ
3.600 kJ
778.17 ft.lb
N.m
J
Btu
W.h
Btu
Power
745 .7 W
hp
Standard S1 unit: watt (W), Equivalent unit: J/s or N.m/s
550 ft.lb/s
1.0 W
1.356 W
3.412 Btu/hr 1.341 hp
hp
N.m/s
ft.lb/s
W
kW
Dynamic Viscosity (or Standard S1 unit: Pa.s or N.s/m2 (cP = centipoise)
100 cP
47.88 Pa.s
10 poise
1000 cP
1 cP
478.8 poise
2
poise
Pa.s
Pa.s
1 mPa.s
lb.s/ft
lb.s/ft2
Kinematic Viscosity ()
10 .764 ft 2 /s 10 4 stoke
m 2 /s
m 2 /s
Standard S1 unit: m2/s (cSt = centistoke)
10 6 cSt 100 cSt
10 6 mm 2 /s
1 cSt
m 2 /s
stoke
m 2 /s
1 mm 2 /s
929.023 stoke
ft 2 /s
For conversions involving Saybolt Universal seconds use the following two equations.
195
t
135
(cSt) = 0.220t t
(cSt) = 0.226t -
t ≤ 100 SUS
t > 100 SUS
Temperature Conversions
Given the Fahrenheit temperature TF in oF, the Celsius temperature TC in oC is
TC = (TF – 32)/1.8
Given the temperature TK in oK, the absolute temperature TR in oR is
TR = 1.8TK
TK = TC + 273.15
TR = TF + 459.67
(cSt) =
 (cP)
SG