How many US gallons are in 1 imperial gallon?

1 imperial gallon equals 1.20095 gal.

How do I convert US gallons back to imperial gallons?

Use the reverse converter: 1 US gallon equals 0.832674 imp gal.

Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.

To convert imperial gallons to US gallons, multiply the value by 1.20094993.

gal = imp gal × 1.20094993

40 imp gal × 1.20094993 = 48.04 gal

Imperial Gallon (imp gal): The UK imperial gallon, defined in 1824 and now exactly 4.54609 litres. Still seen in UK fuel economy figures.
US Gallon (gal): Used for fuel and liquids in the United States. Exactly 3.785411784 litres (231 cubic inches).

How do I convert imperial gallons to US gallons?: To convert imperial gallons to US gallons, multiply the value by 1.20094993.
How many US gallons are in 1 imperial gallon?: 1 imperial gallon equals 1.20095 gal.
How many US gallons are in 10 imperial gallons?: 10 imp gal equals 12.0095 gal.
How do I convert US gallons back to imperial gallons?: Use the reverse converter: 1 US gallon equals 0.832674 imp gal.
Is this converter accurate?: Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.