Conversion from 2 Cubic feet to Gallons

Information about the Cubic foot (ft³)

The cubic foot is a unit of volume equal to 1728 cubic inches, or 28.3168 litres. Its symbol is cu ft, sometimes written ft³. It is the volume of a cube one foot on each side, and it is the unit in which the United States measures natural gas, appliance capacity and air flow, three fields with almost nothing else in common.

Natural gas is its largest use by far. American gas meters record consumption in hundreds of cubic feet, bills are issued in thousands, and national reserves are quoted in trillions. Because the energy in a given volume of gas depends on its composition, utilities also publish a heating value per cubic foot, and the bill is the product of the two.

Appliances are sized in it. Refrigerator and freezer capacity in the United States is quoted in cubic feet, so a family refrigerator is about twenty and a chest freezer perhaps seven, and the same convention covers microwave ovens, washing machines and truck cargo boxes. Shoppers compare products by a number that describes usable space rather than external dimensions, which is genuinely more useful.

Air movement uses it per unit time. Fans, extractors, air conditioners and compressors are rated in cubic feet per minute, a figure abbreviated to CFM in every American catalogue. Ventilation standards are written as required air changes, which convert to cubic feet per minute once the room volume is known, so the unit sits on both sides of the calculation.

Materials and freight follow the same scale. Concrete, gravel, mulch and topsoil are sold by the cubic foot in smaller quantities and by the cubic yard in larger ones, twenty-seven cubic feet making one cubic yard. A cubic foot of fresh water weighs 62.4 pounds and holds about 7.48 United States gallons, which are the two figures most often needed alongside it.

Its metric equivalent is not memorable, at 28.3168 litres or 0.0283 cubic metres, and neither is its relationship to the cubic inch, at 1728. Those factors are why engineering outside the United States moved to metric volumes early even where lengths stayed imperial for longer.

One cubic foot equals 1728 cubic inches, about 28.317 litres, about 7.48 US gallons, or about 0.0283 cubic metres.

Information about the Gallon (gal)

The gallon in the imperial system is a unit of volume equal to exactly 4.54609 litres. Its symbol is gal. It contains four quarts, eight pints and 160 imperial fluid ounces, and it is about a fifth larger than the United States gallon, a difference that causes more confusion than any other single discrepancy between the two systems.

Its original definition was elegant. The Weights and Measures Act of 1824 fixed the imperial gallon as the volume occupied by ten pounds of distilled water at sixty-two degrees Fahrenheit under a barometric pressure of thirty inches of mercury. That tied liquid measure directly to the avoirdupois pound, so a gallon of water weighed ten pounds and a pint weighed a pound and a quarter. In 1985 the definition was replaced by the exact metric figure, but the old relationship still holds to within a fraction of a per cent.

Fuel economy keeps it in daily use. British and Irish drivers describe consumption in miles per gallon even though fuel has been sold in litres since the 1990s, and the figure is an imperial one. The same car scores about twenty per cent higher in British miles per gallon than in American, purely because the gallon is larger, which is why cross-Atlantic comparisons of efficiency are meaningless unless the gallon is specified.

Legal use in Britain is now narrow but real. Draught beer and cider must be sold in pints, half pints or third pints, and milk in returnable containers may be sold in pints, which keeps the whole imperial chain alive by keeping its smallest working member alive. Several Caribbean territories still sell motor fuel by the imperial gallon.

The difference from the American gallon is worth stating plainly. One imperial gallon is 4.546 litres and one United States gallon is 3.785, so an imperial gallon is 1.2 United States gallons. Recipes, fuel figures, tank capacities and chemical dilutions all break if the wrong one is assumed, and the error is large enough to matter but small enough to look plausible.

Below it the chain runs quart, pint, gill and fluid ounce, each a quarter or a fifth of the one above rather than a decimal step. That structure was designed for dividing a container by halving it repeatedly, which is a practical merit when pouring and a serious nuisance when calculating.

One imperial gallon equals 4.54609 litres, 8 imperial pints, 160 imperial fluid ounces, or about 1.201 US gallons.