Area-length-volume

1 acre = 43,560 ft2 = 4,047 m2

1 acre-foot = 1.2335 × 103 m3

1 cubic foot (ft3) = 0.0283 m3

1 hectare (ha) = 10,000 m2 = 2.47 acres

1 square mile (sq mi) = 2.59 × 106 m2

Pressure

1 atmosphere = 76.0 cm Hg = 1,013 millibars (mbar)

1 bar = 0.9869 atmosphere

1 pascal (Pa) = 0.9869 × 10-5 atmosphere = 1 × 10-2 mbar = 10 mbar = 1.4504 × 10-4 pounds per square inch (psi)

Carbon and Carbon dioxide

1 mole C/liter = 12.011 × 10-3 Gt C/km3

1 ppm by volume of atmosphere CO2 = 2.13 Gt C

1 mole CO2 = 44.009 g CO2 = 12.011 g C

1 g C = 0.083 mole CO2 = 3.664 g CO2

Energy

1 quad = 1055 × 1015 joules

1 kcal = 4184 joules

1 mtce = 29.29 × 109 joules

1 boe = 6119 × 106 joules

1 mtoe = 44.76 × 109 joules

1 m3 gas = 37.26 × 106 joules

1 TWyr = 31.54 × 1018 joules