Conversion formula

The conversion factor from cubic inches to gallons is 0.0043290043290138, which means that 1 cubic inch is equal to 0.0043290043290138 gallons:

1 in3 = 0.0043290043290138 gal

To convert 721 cubic inches into gallons we have to multiply 721 by the conversion factor in order to get the volume amount from cubic inches to gallons. We can also form a simple proportion to calculate the result:

1 in3 → 0.0043290043290138 gal

721 in3 → V_(gal)

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

V_(gal) = 721 in3 × 0.0043290043290138 gal

V_(gal) = 3.121212121219 gal

The final result is:

721 in3 → 3.121212121219 gal

We conclude that 721 cubic inches is equivalent to 3.121212121219 gallons:

721 cubic inches = 3.121212121219 gallons

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 gallon is equal to 0.32038834951386 × 721 cubic inches.

Another way is saying that 721 cubic inches is equal to 1 ÷ 0.32038834951386 gallons.

Approximate result

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

721 in3 ≅ 3.121 gal

An alternative is also that one gallon is approximately zero point three two times seven hundred twenty-one cubic inches.

Conversion table

cubic inches to gallons chart

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