Useful Conversions between standard and imperial unit system.

Temperature

Literacy

Fahrenheit: denoted as °F; pronounced as FEH-ruhn-hite.

Conversion
\(F = (9/5)C+32 \)
\(C = (5/9)(F-32) \)

where \(F\) is temperature value in °F and\(C\) is that in °C.

Frequently Used Values

  • Boiling Point (100°C): 212 °F
  • Freezing Point (0°C): 32 °F
  • Comfortable Environment (25°C): 77°F
  • A change of 5°C equals a change of 9°F

Length

Literacy

Inch: denoted as ″ or in.
Foot: denoted as ′ or ft; pluralized as “feet”
Yard: denoted as yd.
Mile: (statute mile) denoted as mi.

Conversion
\(1 inch = 2.54 cm \)
\(1 cm \approx 0.3937 inches \)
\(1 foot = 12 inches = 0.3048 m \)
\(1 m \approx 3.2808 feet \)
\(1 yard = 3 feet = 36 inches = 0.914 m \)
\(1 m \approx 1.0936 yards \)
\(1 mile = 1760 yards = 5280 feet = 1.60934 km \)
\(1 km \approx 0.62137 miles \)

Area

Literacy

Square Inch: denoted as sq in.
Square Foot: denoted as sq ft.
Square Yard: denoted as sq yd.
Acre: denoted as ac; pluralized as acres; pronounced as EI-curr.

Conversion
\(1 sq in = 6.5416 cm^2 \)
\(1 cm^2 \approx 0.155 sq in \)
\(1 sq ft = 144 sq in \approx 9.29 dm^2 \)
\(1 dm \approx 0.10764 feet \)
\(1000 sq ft \approx 92.9 m^2\)
\(100 m^2 \approx 1076 sq ft\)
\(1 sq yd = 9 sq ft \approx 0.836 m^2 \)
\(1 m^2 \approx 1.19599 yards \)
\(1 acre = 4840 sq yd = 43560 sq ft \approx 4046.86 m^2 \)
\(1 km^2 \approx 247.105 acre \)

(Liquid) Volume

Literacy

Ounce: (Fluid Ounce) Denoted as fl oz.
Cup: Denoted as cup.
Pint: Denoted as pt.
Quart: Denoted as qt.
Gallon: (US Gallon) Denoted as gal.

Conversion
\(1 fl oz \approx 29.5735 ml \)
\(1 L \approx 33.814 fl oz \)
\(1 cup = 8 fl oz \approx 236.588 ml \)
\(1 L \approx 4.22675 cups \)
\(1 pint = 2 cups = 16 fl oz \approx 473.1765 ml\)
\(1 L \approx 2.11338 pints \)
\(1 quart = 2 pints = 32 fl oz \approx 946.353 ml\)
\(1 L \approx 1.0567 quarts \)
\(1 gal = 4 quarts = 8 pints = 128 fl oz \approx 3.7854 L\)
\(1 L \approx 0.2642 gal \)

By The Way

The word ounce ultimately comes from the Latin word uncia, meaning "one-twelfth." (This is also where we get the word inch.) In Italian, this became onzo, which is where we get both the word ounce and its abbreviation, oz.

Ounce is a volume unit for liquid (called fluid ounce) or a mass unit for solid.

Mass

Literacy

Grain: Denoted as fr.
Ounce: Denoted as oz.
Pound: Denoted as lb.
Ton:(Short ton) Denoted as Ton.

By The Way

There is a "long ton" which is 2240 lbs. Both "tons" are different from the standard Metric Ton, or Tonne; 1 Tonne is 1000kg, or about 2,204.6 pounds, heavier than both 1 short ton and 1 long ton.

Conversion
\(1 gr \approx 64.8 mg \)
\(1 g \approx 15.43236 gr \)
\(1 oz = 437.5 gr \approx 28.35 g \)
\(1 kg \approx 35.274 oz \)
\(1 lb = 16 oz = 7000 gr \approx 453.59 g \)
\(1 kg \approx 2.2046 lbs \)
\(1 ton = 2000 lbs \approx 907.1847 kg \)
\(1 tonne \approx 1.10231 tons \)

By The Way

"lb" comes from the Latin word Libra, meaning balance or scales(as in the astrological sign), but it also stood for the ancient Roman unit of measure libra pondo), meaning "a pound by weight". We got the word "pound" in English from the pondo part of the libra pondo but our abbreviation comes from the libra.