## Conversion formula

The conversion factor from gallons to fluid ounces is 128, which means that 1 gallon is equal to 128 fluid ounces:

1 gal = 128 fl oz

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

1 gal → 128 fl oz

21 gal → V(fl oz)

Solve the above proportion to obtain the volume V in fluid ounces:

V(fl oz) = 21 gal × 128 fl oz

V(fl oz) = 2688 fl oz

The final result is:

21 gal → 2688 fl oz

We conclude that 21 gallons is equivalent to 2688 fluid ounces:

21 gallons = 2688 fluid ounces

## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 fluid ounce is equal to 0.00037202380952381 × 21 gallons.

Another way is saying that 21 gallons is equal to 1 ÷ 0.00037202380952381 fluid ounces.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one gallons is approximately two thousand six hundred eighty-eight fluid ounces:

21 gal ≅ 2688 fl oz

An alternative is also that one fluid ounce is approximately zero times twenty-one gallons.

## Conversion table

### gallons to fluid ounces chart

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

gallons (gal) fluid ounces (fl oz)
22 gallons 2816 fluid ounces
23 gallons 2944 fluid ounces
24 gallons 3072 fluid ounces
25 gallons 3200 fluid ounces
26 gallons 3328 fluid ounces
27 gallons 3456 fluid ounces
28 gallons 3584 fluid ounces
29 gallons 3712 fluid ounces
30 gallons 3840 fluid ounces
31 gallons 3968 fluid ounces