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 643.5 fluid ounces into gallons we have to multiply 643.5 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

643.5 fl oz → V_(gal)

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

V_(gal) = 643.5 fl oz × 0.0078125 gal

V_(gal) = 5.02734375 gal

The final result is:

643.5 fl oz → 5.02734375 gal

We conclude that 643.5 fluid ounces is equivalent to 5.02734375 gallons:

643.5 fluid ounces = 5.02734375 gallons

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 gallon is equal to 0.1989121989122 × 643.5 fluid ounces.

Another way is saying that 643.5 fluid ounces is equal to 1 ÷ 0.1989121989122 gallons.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six hundred forty-three point five fluid ounces is approximately five point zero two seven gallons:

643.5 fl oz ≅ 5.027 gal

An alternative is also that one gallon is approximately zero point one nine nine times six hundred forty-three point five 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