| Quantity (1) |
Typical Applications |
U.S. Customary Unit |
Unit Symbol |
Metric Unit |
Unit Symbol |
U.S. to Metric |
Metric to U.S. |
| Space & Time |
| volume per unit time | flow rate of fluids |
gallon per minute |
gpm |
cubic meter per hour |
m3/h |
0.2271 |
4.403 |
| velocity, linear |
fluid velocity |
foot per minute |
fpm |
meter per second |
m/s |
0.00508 (9) |
196.9 |
| foot per second |
fps |
meter per second |
m/s |
0.3048 (9) |
3.281 |
| volume |
fluid volume capacity |
cubic inch |
in3 |
milliliter
[cm]3 (2) |
mL (3) |
16.39 |
0.06102 |
| cubic foot |
ft3 |
cubic meter |
m3 |
0.02832 |
35.31 |
| gallon |
gal |
cubic meter |
m3 |
0.003785 |
264.2 |
| quart |
qt |
liter |
L |
0.9464 |
1.057 |
| length |
dimensions of sumps & pits |
foot(and inch) |
ft. or ' |
meter |
m |
0.3048 (9) |
3.281 |
| in or " |
meter |
m |
0.0254 (9) |
1/0.0254 (9) |
| mechanical engineering drawings |
inch |
in or " |
millimeter |
mm |
25.4 (9) |
1/25.4 (9) |
| coating thickness, surface finish, filter particle size |
mil |
|
micrometer |
µm |
25.4 (9) |
1/25.4 (9) |
| microinch |
µin |
micrometer |
µm |
0.0254 (9) |
1/0.0254 (9) |
| micron |
|
micrometer |
µm |
1 (9) |
1 (9) |
| area |
surface area, flow area |
square foot |
ft2 |
square meter |
m2 |
0.09290 |
10.76 |
| square inch |
in2 |
square millimeter |
mm2 |
645.2 |
0.001550 |
| acceleration |
|
foot per second-squared |
ft/S2 |
meter per second squared |
m/S2 |
0.3048 (9) |
3.281 |
| Mechanics |
| fluid energy |
head of fluid |
foot |
ft or ' |
meter |
m |
0.3048 (9) |
3.281 |
| pressure |
fluid pressure or vacuum(NPSH) |
pound-force per sq. in. (psi) |
Ibf/in2 |
kilopascal
[kN/m2] |
kPa |
6.895 |
0.1450 |
inch of mercury
[60°F] |
inHg |
kilopascal |
kPa |
3.377 |
0.2961 |
inch of water
[60°F] |
inH20 |
kilopascal |
kPa |
0.2488 |
4.019 |
| sound pressure level reference (4) |
microbar [0.0002µbar] |
µbar |
micropascal
[20µPa] |
µPa |
100,000 |
0.00001 |
| specific speed |
centrifugal pump impeller | |
 |
|
 |
1.162 |
0.8608 |
| specific speed |
centrifugal pump impeller |  |
|
 |
UNITLESS
(radians) |
0.0003656 |
2735 |
| viscosity, dynamic |
|
centipoise |
cP |
millipascal-second |
mPa•s |
1 (9) |
1 (9) |
| viscosity, kinematic |
|
centistokes (5) |
cSt |
square-millimeter per second |
mm2S |
1 (9) |
1 (9) |
| power(see also heat) |
mechanical power |
horsepower
[550ft•Ibf/s] |
hp |
kilowatt
[kJ/s] (6) |
kW |
0.7457 |
1.341 |
| mass |
equipment mass (weight) |
pound
(decimalized; do not use ounces with pounds) |
lb or # |
kilogram |
kg |
0.4536 |
2.205 |
| ounce |
oz |
gram |
g |
28.35 |
0.03527 |
density
(mass density) |
density of solids & fluids |
pound per cubic foot |
lb/ft3 |
kilogram per cubic meter |
kg/m3 |
16.02 |
0.06243 |
moment of inertia
(dynamic) |
rotor inertia |
pound foot-squared |
lb•ft2 |
kilogram meter-squared |
kg•m2 |
0.04214 |
23.73 |
| energy, work(see also heat) |
force times distance |
foot pound-force |
ft•Ibf |
joule [N•m] (6) |
J |
1.356 |
0.7376 |
| force |
|
pound-force (decimalized; do not use ounces) |
Ibf |
newton |
N |
4.448 |
0.2248 |
| moment of force, torque and bending moment |
bolt tightening, shaft torque, beam stress and deflection calculations |
pound-force foot |
Ibf•ft |
newton-meter |
N•m |
1.356 |
0.7376 |
| pound-force inch |
Ibf•in |
newton-meter |
N•m |
0.1130 |
8.851 |
| unbalance |
impeller, rotor |
ounce-inch |
oz &•in |
gram-millimeter |
g•mm |
720.1 |
0.001389 |
| Heat |
| temperature |
temperture |
degree Fahrenheit |
°F |
degree Celsius (7) |
°C |
(tF-32) x 5/9 (9) |
(tCx1.8)+32 (9) |
| interval between two temperatures |
degree Farenheit
[ tF] |
°F |
kelvin
[tK = tC] |
K |
5/9 (9) |
1.8 (9) |
| heat(energy) |
|
British thermal unit |
Btu (8) |
kilojoule |
kJ |
1.055 |
0.9478 |
| heat flow rate (power) |
heat rejection rate, air conditioning power |
British thermal unit per minute |
Btu/min |
watt [J/s] (6) |
W |
17.58 |
0.05687 |
