## Conversion formula

The conversion factor from cups to gallons is 0.0625, which means that 1 cup is equal to 0.0625 gallons:

1 cup = 0.0625 gal

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

1 cup → 0.0625 gal

21 cup → V(gal)

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

V(gal) = 21 cup × 0.0625 gal

V(gal) = 1.3125 gal

The final result is:

21 cup → 1.3125 gal

We conclude that 21 cups is equivalent to 1.3125 gallons:

21 cups = 1.3125 gallons

## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 gallon is equal to 0.76190476190476 × 21 cups.

Another way is saying that 21 cups is equal to 1 ÷ 0.76190476190476 gallons.

## Approximate result

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

21 cup ≅ 1.313 gal

An alternative is also that one gallon is approximately zero point seven six two times twenty-one cups.

## Conversion table

### cups to gallons chart

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

cups (cup) gallons (gal)
22 cups 1.375 gallons
23 cups 1.438 gallons
24 cups 1.5 gallons
25 cups 1.563 gallons
26 cups 1.625 gallons
27 cups 1.688 gallons
28 cups 1.75 gallons
29 cups 1.813 gallons
30 cups 1.875 gallons
31 cups 1.938 gallons