Conversion formula

The conversion factor from gallons to cubic feet is 0.1336805555555, which means that 1 gallon is equal to 0.1336805555555 cubic feet:

1 gal = 0.1336805555555 ft3

To convert 21.5 gallons into cubic feet we have to multiply 21.5 by the conversion factor in order to get the volume amount from gallons to cubic feet. We can also form a simple proportion to calculate the result:

1 gal → 0.1336805555555 ft3

21.5 gal → V_(ft3)

Solve the above proportion to obtain the volume V in cubic feet:

V_(ft3) = 21.5 gal × 0.1336805555555 ft3

V_(ft3) = 2.8741319444433 ft3

The final result is:

21.5 gal → 2.8741319444433 ft3

We conclude that 21.5 gallons is equivalent to 2.8741319444433 cubic feet:

21.5 gallons = 2.8741319444433 cubic feet

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 cubic foot is equal to 0.34793113862896 × 21.5 gallons.

Another way is saying that 21.5 gallons is equal to 1 ÷ 0.34793113862896 cubic feet.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one point five gallons is approximately two point eight seven four cubic feet:

21.5 gal ≅ 2.874 ft3

An alternative is also that one cubic foot is approximately zero point three four eight times twenty-one point five gallons.

Conversion table

gallons to cubic feet chart

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