# 21 US dry barrels in US gallons

## Conversion

21 US dry barrels is equivalent to 641.454545454545 US gallons.^{[1]}

## Conversion formula

How to convert 21 US dry barrels to US gallons?

We know (by definition) that: $1\mathrm{drybarrel}\approx 30.5454545454545\mathrm{usgallon}$

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

$\frac{1\mathrm{drybarrel}}{21\mathrm{drybarrel}}\approx \frac{30.5454545454545\mathrm{usgallon}}{x\mathrm{usgallon}}$Now, we cross multiply to solve for our unknown $x$:

$x\mathrm{usgallon}\approx \frac{21\mathrm{drybarrel}}{1\mathrm{drybarrel}}*30.5454545454545\mathrm{usgallon}\to x\mathrm{usgallon}\approx 641.4545454545445\mathrm{usgallon}$Conclusion: $21\mathrm{drybarrel}\approx 641.4545454545445\mathrm{usgallon}$

## Conversion in the opposite direction

The inverse of the conversion factor is that **1 US gallon is equal to 0.00155895691609977 times 21 US dry barrels**.

It can also be expressed as: 21 US dry barrels is equal to $\frac{1}{\mathrm{0.00155895691609977}}$ US gallons.

## Approximation

An approximate numerical result would be: **twenty-one US dry barrels is about six hundred and forty-one point four five US gallons**, or alternatively, *a US gallon is about zero times twenty-one US dry barrels*.

## 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.