How many imperial gallons are in 1 US gallon?

1 US gallon equals 0.832674 imp gal.

How do I convert imperial gallons back to US gallons?

Use the reverse converter: 1 imperial gallon equals 1.20095 gal.

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

To convert US gallons to imperial gallons, multiply the value by 0.832674185.

imp gal = gal × 0.832674185

40 gal × 0.832674185 = 33.31 imp gal

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

How do I convert US gallons to imperial gallons?: To convert US gallons to imperial gallons, multiply the value by 0.832674185.
How many imperial gallons are in 1 US gallon?: 1 US gallon equals 0.832674 imp gal.
How many imperial gallons are in 10 US gallons?: 10 gal equals 8.32674 imp gal.
How do I convert imperial gallons back to US gallons?: Use the reverse converter: 1 imperial gallon equals 1.20095 gal.
Is this converter accurate?: Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.