INTERNATIONAL SYSTEM OF UNITS (SI)
SI units are widely used in scientific work. All the SI fundamental units and derived units are listed on this page, as well as the universal constants. Prefixes are applied to the SI names of units to indicate multipliers of the basic unit
 

SI Prefixes
Factor Name  Symbol
1024 yotta Y
1021 zetta Z
1018 exa E
1015 peta P
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
101 deka da
 
Factor Name  Symbol
10-1 deci d
10-2 centi c
10-3 milli m
10-6 micro
10-9 nano n
10-12 pico p
10-15 femto f
10-18 atto a
10-21 zepto z
10-24 yocto y

Some commonly used words that predate the SI units have different meanings in different parts of the world, and some abbreviations (for example the letter "M") have more than one meaning. Here is a ;list of the common problem words:

American           British/French/German    Prefix    Aabbreviation     Factor
thousand            thousand                          Kilo       k                         10^3
million               million                              Mega    M                         10^6
illion                  milliard                            Giga      G                         10^9
trillion               billion                               Tera       T                         10^12
quadrillion                                               Peta       P                        10^15
quintillion         trillion                               Exa        E                         10^18
sextillion                                                  Zetta      Z                          10^21
septillion          quadrillion                         Yotta     Y                          10^24

In many industries, the Roman numera; M, meaning 1000 and MM meaning 1 million were, and still are, widely used, not to be confused with the SI prefix M, meaning 1 million. Sometimes MM is shown in lower case as mm (for example mmcf/d, meaning 1 million cubic feet per day), not to be confused woth the SI unit mm (millimeter). The SI prefix k, meaning 1000, is often written as a caputal letter K, in keeping with the capitalization of many other prefixes for positive powers of 10 (for example M, G, T. etc).

 

Unfortunately, much of the work done in the oilfields uses a mixed set of units composed of British units (called English units in this Handbook) , CGS Units (an early form of metric units), and SI Units (called Metric units in this Handbook). Examples of English units are the foot, mile, and pound. Examples of Metric units are the meter, kilometer, and kilogram. Conversion back and forth between sets of units is a constant task for a petrophysicist.

A lengthy list of conversions is available at the bottom of this page. A useful freeware units conversion calculator can be downloaded HERE. This is an executable (.EXE) file and may be blocked by your security settings.

LIST OF SI UNITS
UNIT SYMBOL DERIVATION BASE UNITS REPRESENTING
ampere A -- A electric current
becquerel Bq 1/s s-1 activity
candela cd -- cd luminous intensity
coulomb C A s A s charge
farad F A s/V kg-1 m-2 s4 A2 capacitance
gray Gy J/kg m2 s-2 absorbed dose
henry H V s/A kg m2 s-2 A-2 inductance
hertz Hz 1/s s-1 frequency
joule J N m kg m2 s-2 energy
kelvin [footnote 1] K -- K temperature
kilogram kg -- kg mass
lumen lm cd sr cd sr luminous flux
lux lx lm/m2 cd sr m-2 illumination
metre m -- m length
mole mol -- mol amount of substance
newton N kg m/s2 kg m s-2 force
ohm O [footnote 2] V/A kg m2 s-3 A-2 resistance
pascal Pa N/m2 kg m-1 s-2 pressure
radian rad -- rad plane angle
second s -- s time
siemens S 1/O kg-1 m-2 s3 A2 electric conductance
sievert Sv J/kg m2 s-2 dose equivalent
steradian sr -- sr solid angle
tesla T Wb/m2 kg s-2 A-1 magnetic flux density
volt V W/A kg m2 s-3 A-1 voltage
watt W J/s kg m2 s-3 power
weber Wb V s kg m2 s-2 A-1 magnetic flux
Non-SI unit approved for use with SI.
UNIT SYMBOL Value in SI Units
minute min 60 s
hour h 60 min = 3600 s
day d 24 h = 86 400 s
degree deg  (pi/180) rad
arcminute ', arcmin (1/60) deg = (pi/10 800) rad
arcsecond ", arcsec (1/60)' = (pi/648 000) rad
litre l, L [footnote 4] 1 dm3 = 10-3 m3
tonne t 103 kg
electronvolt eV (1.602 177 33 +- 0.000 000 49) x 10-19 J
unified atomic mass unit u (1.660 540 2 +- 0.000 001 0) x 10-27 kg
nautical mile -- 1852 m
knot -- 1 nautical mile per hour = (1852/3600) m/s
angstrom A [footnote 5] 10-10 m
are a 1 dam2 = 102 m2
hectare ha 104 m2
barn b 10-28 m2
bar bar 105 Pa
gal Gal 10-2 m/s2
curie Ci 3.7 x 1010 Bq
roentgen R 2.58 x 10-4 C/kg
rad rd, rad 10-2 Gy
rem rem

 


UNIVERSAL CONSTANTS (SI Units)
 
UNIVERSAL CONSTANTS
CONSTANT SYMBOL VALUE and UNITS
acceleration due to gravity g 9.806 65 m/s2
age of Universe t0 15(5) Gy
atomic mass unit, unified u 931.494 32(28) MeV/c2 =
1.660 540 2(10) x 10-27 kg
astronomical unit au 1.495 978 706 6(2) x 1011 m
Avogadro constant NA 6.022 136 7(36) x 1023 mol-1
Bohr magneton muB 5.788 382 63(52) x 10-11 MeV/T
Bohr radius aoo 0.529 177 249(24) x 10-10 m
Boltzmann constant k 1.380 658(12) x 10-23 J/K =
8.617 385(73) x 10-5 eV/K
cosmic background energy density rhogamma 4.647 7 x 10-34 (T/2.726 K)4 g/cm3 =
0.260 71 (T/2.726 K)4 eV/cm3
cosmic background number density ngamma 410.89 (T/2.726 K)3 cm-3
cosmic background temperature T0 2.726 +- 0.005 K
critical density of Universe rhoc 2.775 366 27 x 1011 h02 MS Mpc-3 =
1.878 82(24) x 10-29 h02 g/cm3 =
1.053 94(13) x 10-5 h02 GeV/cm3
day, mean sidereal dsidereal 23h 56m 04s.090 53
deuteron (2H) mass md 1875.613 39(57) MeV/c2
Earth mass ME 5.973 70(76) x 1024 kg
Earth radius (equatorial) RE 6.378 140 x 106 m
electron charge magnitude e 1.602 177 33(49) x 10-19 C =
4.803 206 8(15) x 10-10 esu
electron mass me 0.510 999 06(15) MeV/c2 =
9.109 389 7(54) x 10-31 kg
electron radius, classical re 2.817 940 92(38) x 10-15 m
electron Compton wavelength lambdabare 3.861 593 23(35) x 10-13 m
entropy density/Boltzmann constant s/k 2.892 4 (T/2.726 K)3 cm-3
fine structure constant alpha 1/137.035 989 5(61)
gravitational constant GN 6.672 59(85) x 10-11 m3/(kg s2) =
6.707 11(86) x 10-39 h c/(GeV/c2)2
Hubble constant H0 100 h0 km/(s Mpc) =
h0/9.778 13 Gy
Hubble constant, normalized h0 0.5 < h0 < 0.85
jansky Jy 10-26 W/(m2 Hz)
light year (deprecated) ly 0.306 6... pc =
0.946 1... x 1016 m
Naperian (natural) logarithm base e 2.718 281 828 459 045 235
nuclear magneton muN 3.152 451 66(28) x 10-14 MeV/T
parsec (au/arcsec) pc 3.085 677 580 7(4) x 1016 m =
3.262... ly
permeability of free space mu0 4 pi x 10-7 N/A2 =
12.566 370 614... x 10-7 N/A2
permittivity of free space epsilon0 8.854 187 817... x 10-12 F/m
pi pi 3.141 592 653 589 793 238
Planck constant h 6.626 075 5(40) x 10-34 J s
Planck constant, reduced hbar 1.054 572 66(63) x 10-34 J s =
6.582 122 0(20) x 10-22 MeV s
Planck mass mP 1.221 047(79) x 1019 GeV/c2 =
2.176 71(14) x 10-8 kg
proton (1H) mass mp 938.272 31(28) MeV/c2 =
1.672 623 1(10) x 10-27 kg =
1.007 276 470(12) u =
1836.152 701(37) me
Rydberg energy h c Roo 13.605 698 1(40) eV
Schwarzschild radius of Sun 2 GN MS/c2 2.953 250 08 km
speed of light in vacuum c 299 792 458 m/s
Stefan-Boltzmann constant sigma 5.670 51(19) x 10-8 W/(m2 K4)
strong coupling constant alphas 0.118(3)
Sun distance from Core Ro 8.0(5) kpc
Sun luminosity LS 3.846 x 1026 W
Sun mass MS 1.988 92(25) x 1030 kg
Sun radius (equatorial) RS 6.96 x 108 m
Sun speed around Core Thetao 220(20) km/s
Sun speed to cosmic background   369.5 +- 3.0 km/s
Thompson cross section sigmaT 0.665 246 16(18) barn
W+- boson mass mW 80.33(15) GeV/c2
Wien displacement law constant b 2.897 756(24) x 19) x 10-3 m K
year, sidereal (fixed star to fixed star, 1994) ysidereal 31 558 149.8 s
year, tropical (equinox to equinox, 1994) y 31 556 925.2 s
Z0 boson mass mZ 91.187(7) GeV/c2
 

OILFIELD UNITS CONVERSION TABLE

 

OILFIELD UNITS CONVERSION TABLE

Original Unit

Multiplied
By

Conversion
Factor

Equals

Final Unit

A
acres

x

0.404 69

=

hectares
acres

x

43,560

=

square feet (ft2)
acres

x

4,046.873

=

square meters (m2)
acre-feet

x

43,560

=

cubic feet (ft3 or cf)
acre-feet

x

7,758

=

barrels
angstrom units

x

1.0E-10

=

meters (m)
atmospheres

x

14.70

=

pounds/square inch
atmospheres

x

1.033

=

kilograms/square centimeter
atmospheres

x

1.013250E+05

=

pascal
atmospheres

x

33.90

=

Feet of water
atmospheres

x

76.0

=

centimeter of mercury
barrels (crude oil)

x

5.6146

=

cubic feet of crude oil
barrels (crude oil)

x

0.158 987 3

=

cubic meters of crude oil
barrels (crude oil)

x

42

=

US gallons of crude oil, US
barrels (crude oil)

x

158.987 3

=

liters of crude oil
barrels (crude oil)

x

0.136

=

metric tons of crude oil
barrels/day

x

0.0292

=

Gallons(US)/minute
barrels/day

x

1.84

=

cubic centimeters/second
barrels (crude oil)

x

0.15

=

short tons of crude oil
barrels, US liquid

x

0.75

=

barrels of crude oil
barrels, US liquid

x

31.5

=

gallons, US
bars

x

0.98

=

atmospheres
bars

x

14.50

=

pounds/square inch
British thermal units (Btu)

x

3.931E-04

=

horsepower-hours
British thermal units (Btu)

x

0.000 292 8

=

kilowatthours (kWh)
bushels, US

x

0.035 239 07

=

cubic meters (m3)
calories (cal)

x

4.186 8

=

joules (J)
centimeters (cm)

x

0.394

=

inches (in)
centimeters of mercury

x

0.44

=

feet of water
centimeters/second

x

0.036

=

kilometers/hour
centipoise

x

0.01

=

poise
centipoise

x

0.01

=

grams/cm-sec
centipoise

x

0.0010

=

pascal-second
centipoise

x

6.72E-04

=

pounds/ft-sec
cubic centimeters (cm3)

x

3.531E-05

=

cubic feet (ft3 or cf)
cubic centimeters (cm3)

x

0.06102

=

cubic inches (in3)
cubic centimeters (cm3)

x

2.642E-04

=

gallons, US liquid
cubic centimeters (cm3)

x

1.0E-03

=

liters (L)
cubic feet (ft3 or cf)

x

28,320

=

cubic centimeters (cm3)
cubic feet (ft3 or cf)

x

1728

=

cubic inches (in3)
cubic feet (ft3 or cf)

x

7.48

=

gallons, US liquid
cubic feet (ft3 or cf)

x

28.316 8

=

liters (L)
cubic feet (ft3 or cf)

x

2.831685E-02

=

cubic meters
cubic feet/minute

x

472

=

cubic centimeters/second
cubic feet/minute

x

4.72E-4

=

cubic meters/second
cubic feet/minute

x

0.12

=

gallons/second
cubic feet/minute

x

0.471 947 4

=

liters/second
cubic inches (in3)

x

16.38706

=

cubic centimeters (cm3)
cubic inches (in3)

x

1.639E-05

=

cubic meters (m3)
cubic inches (in3)

x

4.329E-03

=

gallons (gal)
cubic inches (in3)

x

0.016387 06

=

liters (L)
cubic meters (m3)

x

35.315

=

cubic feet (ft3 or cf)
cubic meters (m3)

x

264.20

=

gallons, US liquid
cubic meters (m3)

x

1,000

=

liters (L)
cubic meters/sec (m3/s)

x

15,850

=

gallons/minute
cubic meters/sec (m3/s)

x

2118

=

cubic feet/minute
cubic meters/sec (m3/s)

x

60,000

=

liters/minute
cycles/second

x

1.0

=

hertz
darcy

x

0.9869E-12

=

meter squared
days (mean solar)

x

86,400

=

seconds
degrees (angle)

x

0.0111

=

quadrants
degrees (angle)

x

0.017 453 29

=

radians
degrees (angle)

x

3,600

=

seconds
degrees/second

x

0.16667

=

revolutions/minute
dynes

x

1.0E-05

=

joules/meter (newtons)
dynes/square centimeter

x

1.0E-06

=

bars
em (pica)

x

0.42

=

centimeters (cm)
ergs

x

1.0E-07

=

joules (J)
ergs

x

2.78E-14

=

kilowatthours (kWh)
ergs/second

x

1.3E-10

=

horsepower (hp)
ergs/second

x

1.0E-10

=

kilowatts
feet (ft)

x

30.48

=

centimeters (cm)
feet (ft)

x

12

=

inches (in)
feet (ft)

x

0.3048

=

meters (m)
feet (ft)

x

1.645E-04

=

miles (nautical)
feet (ft)

x

1.894E-04

=

miles (statute)
feet of water

x

0.029499

=

atmospheres of water
feet of water

x

0.8826

=

inches of mercury
feet of water

x

0.433515

=

pounds/square inch
feet/minute

x

0.5080

=

centimeter/second
feet/second

x

1.09728

=

kilometers/hour
feet/second

x

0.59248

=

knots
feet/second

x

0.681818

=

miles/hour
foot-candles

x

10.763 91

=

lumens/square meter
foot-pounds

x

3.77E-07

=

kilowatthours (kWh)
foot-pounds/minute

x

2.26E-05

=

kilowatts (kW)
foot-pounds/sec

x

0.00181

=

horsepower
gallons, US (gal)

x

0.031 75

=

barrels
gallons, US (gal)

x

0.02381

=

barrels of crude oil
gallons, US (gal)

x

3,785.41

=

cubic centimeters (cm3)
gallons, US (gal)

x

0.1337

=

cubic feet (ft3 or cf)
gallons, US (gal)

x

3.785412E-03

=

cubic meters (m3)
gallons, US (gal)

x

0.832675

=

gallons, imperial
gallons, US (gal)

x

3.785412

=

liters (L)
gallons, liquid British imperial

x

1.2014

=

gallons, US liquid
gallons of crude oil

x

0.02380952

=

barrels of crude oil
gallons/minute, US

x

8.0208

=

cubic feet/hour
gallons/minute, US

x

0.134

=

cubic feet/minute
gallons/minute, US

x

6.309E-05

=

cubic meters/sec
gausses

x

1.0E-04

=

webers/square meter
grains

x

0.064798 91

=

grams (g)
grams (g)

x

0.0353

=

ounces
grams (g)

x

2.204623E-03

=

pounds (lb)
grams/centimeter

x

5.6E-03

=

pounds/inch
grams/cubic centimeter

x

62.43

=

pounds/cubic foot
grams/cubic centimeter

x

8.347

=

pounds/gallon
grams/liter

x

1,000

=

parts/million
grams/liter

x

8.34

=

pounds/1,000 gallons
grams/liter

x

0.06243

=

pounds/cubic foot
grams/square centimeter

x

2.04816

=

pounds/square foot
gram-calories

x

1.56E-06

=

horsepower-hours
gram-calories

x

1.16E-06

=

kilowatthours (kWh)
hectares (ha)

x

2.471

=

acres
hectares (ha)

x

107,600

=

square feet (ft2)
hectares (ha)

x

10,000

=

square meters (m2)
horsepower (hp)

x

1.014

=

horsepower (metric)
horsepower (hp)

x

42.44

=

British thermal units/minute
horsepower (hp)

x

550

=

foot-pounds/second
horsepower-hour (hp-hr)

x

2.684520E+6

=

Joules
horsepower (hp)

x

0.746043

=

kilowatts
horsepower (metric)

x

0.986

=

horsepower
horsepower (metric)

x

542.5

=

foot-pounds/second
inches (in)

x

2.54

=

centimeters (cm)
inches (in)

x

0.0254

=

meters (m)
inches (in)

x

1.578E-05

=

miles (mi)
inches of mercury

x

0.4912

=

pounds/square inch
inches of water at (4oC)

x

2.458E-03

=

atmospheres
inches of water at (4oC)

x

0.03

=

pounds/square inch
joules (J)

x

9.48E-04

=

British thermal units (Btu)
joules (J)

x

2.778E-04

=

watthours (Wh)
kilograms (kg)

x

2.204 6

=

pounds (lb)
kilograms (kg)

x

9.84E-04

=

tons, long
kilograms (kg)

x

1.1E-03

=

tons, metric (t)
kilograms/sqhare meter

x

1.42E-03

=

pounds/square inch
kilograms/meter

x

0.67197

=

pounds/foot
kilograms/square centimeter

x

0.9678

=

atmospheres
kilograms/square centimeter

x

14.223

=

pounds/square inch
kilograms/square meter

x

9.81E-05

=

bars
kilogram-meters

x

2.72E-06

=

kilowatthours (kWh)
kilometers (km)

x

3,280.84

=

feet (ft)
kilometers (km)

x

0.621 4

=

miles (mi)
kilometers/hour

x

0.91134

=

feet/second
kilometers/hour

x

0.53995

=

knots
kilometers/hour

x

0.62137

=

miles/hour
kilowatts (kW)

x

1.341

=

horsepower (hp)
kilowatts (kW)

x

1,000

=

watts (W)
kilowatthours (kWh)

x

3,413

=

British thermal units (Btu)
kilowatthours (kWh)

x

3.60E+06

=

Joules
liters (L)

x

0.0063

=

barrels of oil
liters (L)

x

0.0084

=

barrels
liters (L)

x

0.035315

=

cubic feet (ft3 or cf)
liters (L)

x

61.02

=

cubic inches (in3)
liters (L)

x

0.264

=

gallons
long tons

x

1,016.047

=

kilograms (kg)
long tons

x

1.016047

=

metric tons (t)
long tons

x

2,240

=

pounds (lb)
long tons

x

1.12

=

short tons (st)
meters (m)

x

3.281

=

feet (ft)
meters (m)

x

6.21E-04

=

miles (statute)
meters/second

x

2.23

=

miles/hour
meters/second

x

196.8

=

feet/minute
metric tons (t)

x

1,000

=

kilograms (kg)
metric tons (t)

x

2,204.62

=

pounds (lb)
metric tons (t)

x

1.1023

=

short tons (st)
metric tons of crude oil

x

7.33

=

barrels (bbl)
microns

x

1.0E-06

=

meters (m)
miles, statute

x

161,000

=

centimeters (cm)
miles, statute

x

5,280

=

feet (ft)
miles, statute

x

1.609344

=

kilometers (km)
miles, statute

x

1,609

=

meters (m)
miles, statute

x

0.868975

=

miles, nautical
miles/hour

x

44.70

=

centimeter/second
miles/hour

x

1.4667

=

feet/second
meters (m)

x

3.281

=

feet
meters (m)

x

6.21E-04

=

miles (statute)
millimeters

x

0.03937

=

inches
milligrams/liter

x

1

=

parts/million
million gallons/day

x

1.5472

=

cubic feet/second
minutes (angles)

x

0.0167

=

degrees
newtons

x

0.22481

=

pounds force
newtons

x

100,000

=

dynes
ounces (oz)

x

28.34

=

grams (g)
ounces (oz)

x

0.0625

=

pounds (lb)
pascal

x

1

=

newton/sq meter
pascal

x

9.871E-06

=

atmosphere
parts/million

x

8.34

=

pounds/million gallon (gal)
pints, US liquid

x

0.125

=

gallons, US (gal)
poise (P)

x

1

=

grams/centimeter second
poundals

x

13,826

=

dynes
pounds (lb)

x

4.45E+05

=

dynes
pounds (lb)

x

453.59

=

grams (g)
pounds (lb)

x

4.5359E-04

=

Tons (metric)
pounds (lb)

x

4.448

=

joules/meter (newtons)
pounds (lb)

x

0.45359237

=

kilograms (kg)
pounds (lb)

x

16

=

ounces (oz)
pounds of water

x

27.68

=

cubic inches (in3)
pounds of water

x

0.11983

=

gallons (gal)
pounds/cubic foot

x

0.1337

=

pounds/gallon (US)
pounds/cubic foot

x

0.006944

=

pounds/sq inch/foot (psi/ft)
pounds/cubic foot

x

0.016026

=

specific gravity
pounds/cubic foot

x

0.016026

=

grams/cubic centimeter
pounds/cubic foot

x

16.026

=

kilograms/cubic meter
pounds/cubic inch

x

27.68

=

grams/cubic centimeter
pounds/cubic inch

x

27,680

=

kilograms/cubic meter
pounds/foot

x

1.4882

=

kilograms/meter
pounds/inch

x

178.60

=

grams/centimeter
pounds/gallon (ppg)

x

0.12005

=

specific gravity
pounds/gallon (ppg)

x

0.052

=

pounds/sq inch/foot (psi/ft)
pounds/gallon (ppg)

x

7.48

=

pounds/cubic foot
pounds/gallon (ppg)

x

0.1198

=

grams/cubic centimeter
pounds/square inch

x

0.0680

=

atmospheres
pounds/square inch

x

2.3095

=

feet of water
pounds/square inch

x

2.03602

=

inches of mercury
pounds/square inch

x

703.0696

=

kilograms/square meter
pounds/square inch

x

6.894757E+03

=

pascal
pounds/square inch

x

144

=

pounds/square foot
pounds/sq inch/foot(psi/ft)

x

19.23

=

pounds/gallon (US)
pounds/sq inch/foot(psi/ft)

x

144

=

pounds/cubic foot
pounds/sq inch/foot (psi/ft)

x

2.3095

=

specific gravity
quadrants, angle

x

90

=

degrees
quadrants, angle

x

1.5708

=

radians
quarts, liquid

x

57.75

=

cubic inches (in3)
quarts, liquid

x

9.46E-04

=

cubic meters (m3)
radians

x

57.29

=

degrees
radians

x

3,438

=

minutes
radians

x

206,000

=

seconds
revolutions

x

360

=

degrees
revolutions

x

4

=

quadrants
revolutions

x

6.283185

=

radians
seconds (angle)

x

2.78E-04

=

degrees
seconds (angle)

x

4.848137E-06

=

radians
short tons (st)

x

0.8929

=

long tons
short tons (st)

x

0.9071847

=

metric tons (t)
short tons (st)

x

2,000

=

pounds (lb)
short tons of crude oil

x

6.65

=

barrels (bbl)
specific gravity

x

1

=

grams/cubic centimeter
specific gravity

x

0.433

=

pounds/sq inch/foot (psi/ft)
specific gravity

x

8.33

=

pounds/gallon (US)
specific gravity

x

350.5

=

pounds/barrel
specific gravity

x

62.4

=

pounds/cubic foot
square centimeters (cm2)

x

1.08E-03

=

square feet (ft2)
square centimeters (cm2)

x

0.1550

=

square inches (in2)
square inch (in2)

x

6.4516

=

square centimeter
square feet (ft2)

x

2.2956E-05

=

acres
square feet (ft2)

x

929.03

=

square centimeters (cm2)
square feet (ft2)

x

144

=

square inches (in2)
square feet (ft2)

x

0.09290304

=

square meters (m2)
square feet (ft2)

x

3.59E-08

=

square miles (mi2)
square kilometers (km2)

x

247.10

=

acres
square kilometers (km2)

x

100

=

hectares
square kilometers (km2)

x

0.386

=

square miles (mi2)
square meters (m2)

x

2.471E-04

=

acres
square meters (m2)

x

10.763915

=

square feet (ft2)
square meters (m2)

x

3.86E-07

=

square miles (mi2)
square miles (mi2)

x

640

=

acres
square miles (mi2)

x

27,900,000

=

square feet (ft2)
square miles (mi2)

x

2.589988

=

square kilometers (km2)
therms

x

100,000

=

BTUs of natural gas
therms

x

1.054804E+08

=

joules (J)
tonnes

x

1.0

=

tons, metric
tons, long

x

1,016.047

=

kilograms (kg)
tons, long

x

1.016047

=

metric tons (t)
tons, long

x

2,240

=

pounds (lb)
tons, long

x

1.12

=

short tons (st)
tons, metric (t)

x

7.33

=

barrels of crude oil
tons, metric (t)

x

1,000

=

kilograms (kg)
tons, metric (t)

x

2,204.62

=

pounds (lb)
tons, short (st)

x

6.65

=

barrels of crude oil
tons, short (st)

x

0.8929

=

long tons
tons, short (st)

x

0.9071847

=

metric tons (t)
tons, short (st)

x

2,000

=

pounds (lb)
watts (W)

x

3.41219

=

British thermal units/hour
watts (W)

x

0.001341

=

horsepower (hp)
watts (absolute)

x

1

=

joules/second
watthours (Wh)

x

3.41219

=

British thermal units (Btu)
watthours (Wh)

x

2,656

=

foot-pounds
weeks

x

168

=

hours
years (mean of 4-year period)

x

365.25

=

days
years (mean of 4-year period)

x

8,766

=

hours
years (mean of 4-year period)

x

526,000

=

minutes (time)
years (mean of 4-year period)

x

31,558,150

=

seconds (time)
years (mean of 4-year period)

x

52.17

=

week
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