21 US gallons in US customary cups

Result

The conversion result is: 21 US gallons is equivalent to 336 US customary cups.[1]

Conversion formula
How to convert 21 US gallons to US customary cups?

We know (by definition) that: 1 usgallon ≈ 16 uscup.

We can set up a proportion to solve for the number of US customary cups.

1 usgallon / 21 usgallon ≈ 16 uscup / x uscup

Now, we cross multiply to solve for our unknown x:

x uscup ≈ (21 usgallon / 1 usgallon) * 16 uscup → x uscup ≈ 336 uscup

Conclusion:

21 usgallon ≈ 336 uscup

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US customary cup is equal to 0.00297619047619048 times 21 US gallons.

It can also be expressed as: 21 US gallons is equal to 1 / 0.00297619047619048 US customary cups.

Approximation

An approximate numerical result would be: twenty-one US gallons is about three hundred and thirty-six US customary cups, or alternatively, a US customary cup is about zero times twenty-one US gallons.

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.