Common unit conversion formula

Area conversion

1 square kilometer (k㎡) = 100 hectares (ha) = 247.1 acres (acre) = 0.386 square miles (mile2)

1 square meter (㎡)=10.764 square feet (ft2)

1 square inch (in2) = 6.452 square centimeters (c㎡)

1 hectare (ha) = 10,000 square meters (㎡) = 2.471 acres (acre)

1 acre (acre)=0.4047 hectares (ha)=4.047×10-3 square kilometers (k㎡)=4047 square meters (m2)

1 acre (acre)=0.4047 hectares (ha)=4.047×10-3 square kilometers (k㎡)=4047 square meters (㎡)

1 square foot (ft2) = 0.093 square meters (㎡)

1 square meter (㎡)=10.764 square feet (ft2)

1 square yard (yd2) = 0.8361 square meters (㎡)

1 square mile (mile2)=2.590 square kilometers (k㎡)

1 mu is approximately equal to 667 square meters

1 square kilometer (km2) = 100 hectares (ha) approximately equal to 1500 mu

Volume conversion

1 US Gel (gi) = 0.118 liters (1) 1 US pint (pt) = 0.473 liters (1)

1 US quart (qt) = 0.946 liters (1) 1 US gallon (gal) = 3.785 liters (1)

1 barrel (bbl) = 0.159 cubic meters (m³) = 42 US gallons (gal) 1 acre·feet = 1234 cubic meters (m³)

1 cubic inch (in3) = 16.3871 cubic centimeters (cm³) 1 British gallon (gal) = 4.546 liters (1)

1 billion cubic feet (bcf) = 28.317 million cubic meters (m³) 1 trillion cubic feet (tcf) = 28.317 billion cubic meters (m³)

1 million cubic feet (MMcf) = 28,317 cubic meters (m³) 1 thousand cubic feet (mcf) = 28.317 cubic meters (m³)

1 cubic foot (ft3) = 0.0283 cubic meters (m³) = 28.317 liters (liter)

1 cubic meter (m³) = 1000 liters (liter) = 35.315 cubic feet (ft3) = 6.29 barrels (bbl)

Mass and density conversion

Mass conversion

1 long ton (long ton) = 1.016 ton (t) 1 kilogram (kg) = 2.205 pounds (lb)

1 pound (lb) = 0.454 kilograms (kg) [constant weight] 1 ounce (oz) = 28.350 grams (g)

1 short ton (sh.ton) = 0.907 tons (t) = 2000 pounds (lb)

1 ton (t) = 1000 kilograms (kg) = 2205 pounds (lb) = 1.102 short ton (sh.ton) = 0.984 long ton (long ton)

Density conversion

1 lb/ft3 (lb/ft3) = 16.02 kg/m3 (kg/m³)

API degree = specific gravity at 141.5/15.5℃-131.5

1 lb/British gallon (lb/gal)=99.776 kg/m3 (kg/m³)

1 Baume density (B) = specific gravity at 140/15.5℃-130

1 lb/in3 (lb/in3) = 27679.9 kg/m3 (kg/m³)

1 pound/US gallon (lb/gal) = 119.826 kg/m3 (kg/m³)

1 pound/(oil) barrel (lb/bbl)=2.853 kg/m3 (kg/m³)

1 kg/m3 (kg/m³)=0.001 g/cm3 (g/cm³)=0.0624 pounds/ft3 (lb/ft3)

Viscosity conversion

Kinematic viscosity conversion

1 St (St)=10-4 m2/s (㎡/s)=1 cm2/s (c㎡/s)

1 ft2/s (ft2/s)=9.29030×10-2 m2/s (㎡/s)

1 centistoke (cSt)=10-6 m2/s (㎡/s)=1 mm2/s (m㎡/s)

Dynamic viscosity conversion

Dynamic viscosity 1 poise (P) = 0.1 Pa·s (Pa·s) 1 centipoise (cP) = 10-3 Pa·s (Pa·s)

1 pound-force second/foot 2 (lbf·s/ft2) = 47.8803 Pa·s (Pa·s)

1 kilogram-force second/m2 (kgf·s, m2)=9.80665 Pa·s (Pa·s)

Force and temperature conversion

Force conversion

1 Newton (N) = 0.225 pound force (lbf) = 0.102 kilogram force (kgf)

1 kilogram force (kgf) = 9.81 cattle (N)

1 pound force (lbf) = 4.45 Newton (N) 1 Dyne (dyn) = 10-5 Newton (N)

Temperature conversion

K=5/9 (°F+459.67) K=°C+273.15

n°F=(5/9·n+32) °F n°F=[(n-32)×5/9]°C

1°F=5/9°C (temperature difference)

Pressure conversion

Pressure 1 bar (bar) = 105 Pa (Pa) 1 dyne/cm2 (dyn/cm2) = 0.1 Pa (Pa)

1 Torr (Torr) = 133.322 Pa (Pa) 1 millimeter of mercury (mmHg) = 133.322 Pa (Pa)

1 millimeter of water column (mmH2O) = 9.80665 Pa (Pa) 1 Project atmospheric pressure = 98.0665 kPa (kPa)

1 kilopascal (kPa) = 0.145 pound force/inch 2 (psi) = 0.0102 kgf/cm2 (kgf/cm2) = 0.0098 atmospheric pressure (atm)

1 pound force/inch 2 (psi) = 6.895 kilopascals (kPa) = 0.0703 kilogram force/cm 2 (kg/c㎡) = 0.0689 bar (bar) = 0.068 atmospheres (atm)

1 Physical atmospheric pressure (atm) = 101.325 kilopascals (kPa) = 14.696 pounds per inch 2 (psi) = 1.0333 bar (bar)

Conversion of heat transfer coefficient, thermal conductivity, and specific heat capacity

Heat transfer coefficient conversion

1 kcal/m2·hour (kcal/㎡·h) = 1.16279 watts/m2 (w/㎡)

1 kcal/(m2·hour·℃)〔1kcal/(㎡·h·℃)〕=1.16279W/(meter2·Kelvin)〔w/(㎡·K)〕

1 British thermal unit/(feet2·hour·°F)〔Btu/(ft2·h·°F)〕=5.67826W/(meter2·Kelvin)〔(w/㎡·K)〕

1m2·hour·℃/kcal (㎡·h·℃/kcal)=0.86000m2·Kelvin/W (㎡·K/W)

Thermal conductivity conversion

1 kcal (meter·hour·°C) [kcal/(m·h·°C)] = 1.16279 watts/(meter·Kelvin) [W/(m·K)]

1 British thermal unit/(feet·hour·°F)〔But/(ft·h·°F) =1.7303W/(meter·Kelvin)〔W/(m·K)〕

Specific heat conversion

1 kcal/(kg·℃) [kcal/(kg·°C)] = 1 British thermal unit/(lb·°F) [Btu/(lb·°F)] = 4186.8 Joules/(kg·Kelvin) [ J/(kg·K)]

Heat conversion

1 calorie (cal) = 4.1868 Joule (J) 1 calorie = 4186.75 Joule (J)

1 kilogram-force meter (kgf·m)=9.80665 joules (J)

1 British thermal unit (Btu) = 1055.06 Joule (J)

1 kilowatt hour (kW·h)=3.6×106 joules (J)

1 foot-pound force (ft·lbf) = 1.35582 Joules (J)

1 metric horsepower hour (hp·h)=2.64779×106 joules (J)

1 British horsepower hour (UKHp·h)=2.68452×106 Joules

1 Joule = 0.10204 kg·m

=2.778×10-7 kilowatts·hour

＝3.777×10-7 metric horsepower hours

＝3.723×10-7 British horsepower hours

=2.389×10-4kcal

=9.48×10－4 British thermal units

Conversion of power, speed, and permeability

Power conversion

1 British thermal unit/hour (Btu/h) = 0.293071 watts (W)

1 kgf·m/s (kgf·m/s)=9.80665 watts (w)

1 cal/s (cal/s) = 4.1868 watts (W) 1 metric horsepower (hp) = 735.499 watts (W)

Speed conversion

1 mile/hour (mile/h) = 0.44704 meters/second (m/s)

1 foot per second (ft/s) = 0.3048 meters per second (m/s)

Permeability conversion

1 Darcy=1000 millidarcy 1 square centimeter (c㎡)=9.81×107 Darcy

Conversion of geothermal gradient, oil and gas production, gas-oil ratio

Geothermal gradient conversion

1°F/100 feet = 1.8°C/100 meters (°C/m)

1°F/km = 2.9°F/mile (°F/mile)=0.055°F/100 feet (°F/ft)

Oil and gas production conversion

1 barrel (bbl) = 0.14 tons (t) (crude oil, global average)

1 trillion cubic feet per day (tcfd) = 28.32 billion cubic meters per day (m³/d) = 10.336 trillion cubic meters per year (m³/a)

1 billion cubic feet per day (bcfd) = 28.32 million cubic meters per day (m³/d) = 10.336 billion cubic meters per year (m³/a)

1 million cubic feet per day (MMcfd) = 28,32 million cubic meters per day (m³/d) = 10,335,500 cubic meters per year (m³/a)

1,000 cubic feet per day (Mcfd) = 28.32 cubic meters per day (m³/d) = 10,336 cubic meters per year (m³/a)

1 barrel/day (bpd)=50 tons/year (t/a) (crude oil, global average)

1 ton (t) = 7.3 barrels (bbl) (crude oil, global average)

Gas-oil ratio conversion

1 cubic foot/barrel (cuft/bbl)=0.2067 cubic meters/ton (m³/t)

Calorific value, heat equivalent conversion

Calorific value conversion

1 barrel of crude oil = 5.8×106 British thermal units (Btu)

1 ton of coal = 2.406×107 British thermal units (Btu)

1 cubic meter of moisture = 3.909×104 British thermal units (Btu)

1 kilowatt hour of hydropower = 1.0235×104 British heat (Btu)

1 cubic meter of dry gas = 3.577×104 British thermal units (Btu) (The above is the average heating value of the United States in 1990)

(Source: American National Standards Institute)

Heat equivalent conversion

1 barrel of crude oil = 5800 cubic feet of natural gas (calculated based on average heating value)

1 cubic meter of natural gas = 1.3300 kilograms of standard coal

1 kg of crude oil = 1.4286 kg of standard coal

Source: Thermal Processing Forum