Imperial gallons to Cubic inches Converter

Imperial gallons (imp gal). An imperial gallon is 4.54609 liters, about 20% more than a US gallon. It is the traditional UK and Commonwealth liquid unit, now largely replaced by liters.

Cubic inches (in³). A cubic inch is 16.387064 milliliters. It is used for engine displacement in the United States and for small volumes in imperial engineering.

US and imperial units are kept separate because they are genuinely different sizes. Confirm which system a source means before trusting a converted figure.

The metric volume units are a clean decimal chain around the liter, so liters to milliliters is a shift of three places and cubic meters to liters is a shift of three the other way. Those pairs a reader can do without a converter.

Every pair that names a US or imperial liquid unit has to go through the definition first, because three of these units differ from a metric unit by amounts too large to round away: a liter is not a quart, a gallon is 3.785411784 liters in the US system and 4.54609 in the imperial one, and a US fluid ounce is not an imperial fluid ounce.

When checking a volume conversion, convert into liters and out again, or measure the container. The mistake that survives every other check is reading a US measure as the imperial unit of the same name, which changes a recipe, a fuel figure or a tank size by about a fifth.