Converting from ounces to gallons is pretty straightforward, but depends on the measurement system you're using. For US measurements, the formula is: 1 gallon / 128 ounces as there are 128 ounces per 1 US gallon while for UK measurements, the formula is: 1 gallon / 160 ounces since there are 160 ounces in 1 UK gallon.
For example, let's imagine you need to convert 6.887 ounces to gallons:
US formula: 6.887 / 128 = .0538 gallons
UK formula: 6.887 / 160 = .0430 gallons
Need to convert Gallons to Ounces? Try our Gallons to Ounces calculator