646 US customary cups in US gallons
Result
The conversion result is: 646 US customary cups is equivalent to 40.375 US gallons.[1]
Conversion formula
How to convert 646 US customary cups to US gallons?
We know (by definition) that: 1 uscup ≈ 0.0625 usgallon.
We can set up a proportion to solve for the number of US gallons.
1 uscup / 646 uscup ≈ 0.0625 usgallon / x usgallon
Now, we cross multiply to solve for our unknown x:
x usgallon ≈ (646 uscup / 1 uscup) * 0.0625 usgallon → x usgallon ≈ 40.375 usgallon
Conclusion:
646 uscup ≈ 40.375 usgallon
Conversion in the opposite direction
The inverse of the conversion factor is that 1 US gallon is equal to 0.0247678018575851 times 646 US customary cups.
It can also be expressed as: 646 US customary cups is equal to 1 / 0.0247678018575851 US gallons.
Approximation
An approximate numerical result would be: six hundred and forty-six US customary cups is about forty point three eight US gallons, or alternatively, a US gallon is about zero point zero two times six hundred and forty-six US customary cups.
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.