Some common metric unites and their english equivalents:


miles × 1.609 = kilometers

miles × 1.1 = nautical miles

nautical miles × 1.852 = kilometers

feet × 0.304 = meters

nautical miles per hour (knots) × 1.852 = kilometers per hour

miles per hour × 1.609 = kilometers per hour

gallons/acre × 9.35 = liters/hectare

acre × 0.404 = hectare

inches × 25.4 = millimeters

fathom × 1.8288 = meters

   

The conversion factor of 294 gallons per tonne is derived from an average specific gravity of 0.83, which corresponds to an API gravity or degree API of 39. Note that API gravity and specific gravity are inversely proportional as per the formulae below. The 294 gallons/tonne conversion unit is also convenient because it happens that 294 gallons = 7 barrels.

API = (141.5/sp gr) − 131.5

sp gr = 141.5/(API + 131.5)



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