Conversion from 100 Decaliters to US Gallons

Information about the Decaliter (daL)

The decalitre is a unit of volume equal to ten litres. Its symbol is daL, and the spelling dekalitre is also accepted. It sits between the litre of the household and the hectolitre of the trade, and although it once had a settled place in European markets it is now among the least written of the metric volume units.

Its historical role was as a physical measure rather than a number. Nineteenth-century French markets sold grain, potatoes, chestnuts and dried beans out of stamped cylindrical vessels holding one decalitre, half a decalitre or a double one, and a trader's set of these was inspected and verified like a set of weights. Selling dry goods by volume was faster than weighing them and needed no balance, so the vessels did real work.

Weighing displaced it. Once cheap accurate scales became universal, dry goods moved to mass, which is fairer to the buyer because it does not depend on how densely a load happens to settle. The decalitre lost its purpose along with the practice, and the vessels survive in museums and in the vocabulary of a few older markets rather than in commerce.

The quantity itself remains perfectly ordinary. Ten litres is a large household bucket, half a jerrycan, the fuel tank of a scooter, or a fortnight of drinking water for one person. It is roughly the volume of a cubic vessel twenty-two centimetres on a side, and it weighs ten kilograms when filled with water.

What killed the unit as a written form was the same pressure that removed deca everywhere else. Metric practice steps by factors of a thousand, so litres serve until about a thousand of them and hectolitres take over for trade quantities. Ten litres is written 10 L, which is shorter than 1 daL, needs no explanation, and sorts correctly beside 5 L and 200 L in the same table.

When the unit does appear, usually in an old record or a translated document, the conversion is a single step. Multiply by ten for litres, divide by ten for hectolitres, and the resulting figure will match modern usage without any loss of precision.

One decalitre equals 10 litres, 0.1 hectolitres, about 2.64 US gallons, or about 2.2 imperial gallons.

Information about the US Gallon (gal US)

The United States gallon is a unit of volume equal to exactly 231 cubic inches, or 3.785411784 litres. Its symbol is gal US. It contains four quarts, eight liquid pints and 128 United States fluid ounces, and it is about a fifth smaller than the imperial gallon still used in Britain and Ireland.

It is older than its British rival. The figure of 231 cubic inches comes from the English wine gallon standardised in 1707 under Queen Anne, which was the common measure across the American colonies. When Britain abolished its several gallons in 1824 and replaced them with a single imperial gallon based on ten pounds of water, the United States simply kept the one it already had, and the two systems have diverged ever since.

Fuel makes it the most politically visible unit in American life. The price of a gallon of gasoline is quoted daily, watched by governments and used as shorthand for the cost of living, and vehicle efficiency is stated in miles per gallon on every window sticker. Because the American gallon is smaller, a car rated at 30 miles per gallon in the United States would be described as 36 in Britain, which is the same car and the same fuel.

The petroleum industry counts in a multiple of it. The barrel of crude oil is defined as 42 United States gallons, a figure fixed in the Pennsylvania oil fields in the 1860s when a 40-gallon barrel plus two gallons of allowance for leakage became the trade standard. Every published figure for world oil production and reserves rests on that convention.

Domestic quantities follow the same measure. Milk, paint, water for the garden, propane and swimming pool chemistry are all sold and dosed by the gallon in the United States, and a gallon of fresh water weighs 8.34 pounds against the imperial gallon's ten. That difference in weight is a useful check when a figure of uncertain origin needs to be identified.

Care with labelling matters when the two gallons meet. A liquid described simply as a gallon in an American document is 3.785 litres and in a British one 4.546, and nothing in the word itself distinguishes them. Writing gal US or specifying litres removes an ambiguity that has caused real errors in shipping, aviation and chemical dosing.

One United States gallon equals 3.785411784 litres, 231 cubic inches, 128 US fluid ounces, or about 0.833 imperial gallons.