Conversion Gallons To Litres. Basically, two sets of measurements are used in the world. One is the Metric System and the other is the Imperial System. The latter came into existence in 1894 in Britain with the Weights and Measures Act and was in use throughout the British Empire. The imperial system of measurement is officially recognized and is widely in use in the United Kingdom, the Republic of Ireland, Australia while in some other countries like India and Malaysia it is used in a limited scale.

The Metric System of Measurements first came into use in France in 1791 as a decimalized system of measurement. Since then, and during the last two centuries up to 1960 many different variation of this system had been in use. But, from that year onwards, the International System of Units had been the internationally recognized metric standard in the world. This is the standard of measurement that is currently used for scientific, commercial and personal purposes universally.   Though this system has a universal application, some countries use both systems concurrently. For example, even though the Units of Measurement Regulations 1995 in the completed United Kingdom's transition into the metric system in that same year, the imperial system still has wide use colloquially among the British people. They speak in terms of pounds and stones for weight, pints and gallons for volume and inches and feet for distance. There is also the peculiar situation in this country where, although it has officially and legally embraced the SI unit system of measurement, there is also the parallel legal and official adaptation of imperial units. For example, the Traffic Sign Regulations in the United Kingdom makes the use of imperial units mandatory in all traffic signs when displaying distances. In some other instances like measuring fuel consumption, though the official method is to use metric units given in terms of liters per 100 kilometer, it is colloquially expressed as miles per gallon. Since both measuring systems are in use in this country in this manner, provisions have been made in the British law to define imperial units in their metric equivalents.  When it comes to fuel people in the United Kingdom think in terms of gallons but the dispensation of fuel is officially done in liters. Hence, the conversion of gallons to liters becomes necessary for proper transactions to take place in fuel sales. There are various methods available to do this conversion. They range from web pages and calculators to ready rekoners and conversion tables.