1 imperial gallon in US gallons

Conversion

1 imperial gallon is equivalent to 1.20094992550486 US gallons.^[1]

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US gallon is equal to 0.832674184628989 times 1 imperial gallon.

It can also be expressed as: 1 imperial gallon is equal to $\frac{1}{0.832674184628989}$ US gallons.

Approximation

An approximate numerical result would be: one imperial gallon is about one point one nine US gallons, or alternatively, a US gallon is about zero point eight three times one imperial gallon.

Units involved

This is how the units in this conversion are defined:

Imperial Gallons

"The imperial (UK) gallon, now defined as exactly 4.54609 litres (about 277.42 cubic inches), is used in some Commonwealth countries and was originally based on the volume of 10 pounds (approximately 4.54 kg) of water at 62 °F (17 °C). The imperial fluid ounce is defined as 1⁄160 of an imperial gallon; there are four quarts in a gallon, two pints in a quart, and 20 Imperial fluid ounces in an imperial pint."

Wikipedia page of imperial gallons

Us Gallons

"The US gallon is legally defined as 231 cubic inches, which is exactly 3.785411784 liters.[2][3] A US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 °F (17 °C), making it about 16.6% lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes the US fluid ounce equal to 1⁄128 of a US gallon."

Wikipedia page of US gallons

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.