Conversion formula

The conversion factor from fluid ounces to gallons is 0.0078125, which means that 1 fluid ounce is equal to 0.0078125 gallons:

1 fl oz = 0.0078125 gal

To convert 21 fluid ounces into gallons we have to multiply 21 by the conversion factor in order to get the volume amount from fluid ounces to gallons. We can also form a simple proportion to calculate the result:

1 fl oz → 0.0078125 gal

21 fl oz → V_(gal)

Solve the above proportion to obtain the volume V in gallons:

V_(gal) = 21 fl oz × 0.0078125 gal

V_(gal) = 0.1640625 gal

The final result is:

21 fl oz → 0.1640625 gal

We conclude that 21 fluid ounces is equivalent to 0.1640625 gallons:

21 fluid ounces = 0.1640625 gallons

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 gallon is equal to 6.0952380952381 × 21 fluid ounces.

Another way is saying that 21 fluid ounces is equal to 1 ÷ 6.0952380952381 gallons.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one fluid ounces is approximately zero point one six four gallons:

21 fl oz ≅ 0.164 gal

An alternative is also that one gallon is approximately six point zero nine five times twenty-one fluid ounces.

Conversion table

fluid ounces to gallons chart

For quick reference purposes, below is the conversion table you can use to convert from fluid ounces to gallons