# Dilution & Boil Off Calculator by Karl S | Updated: March 17, 2021

All of the formula’s used in this calculator have been derived from the following Formula from Ray Daniel’s book, Designing Great Beers.

Designing Great Beers: The Ultimate Guide
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Designing Great Beers goes much more into depth about the key components of beer styles: types of malt, hops, yeast, water chemistry, fermentation temperatures, IBU's, SRM's, etc, etc.

06/28/2022 12:14 am GMT

Beg Volume * Beg Gravity = End Volume * End Gravity

**It should be noted that in the following formula’s, ‘Gravity Points’ are used in place of the beers actual Specific Gravity. (IE – 1.055 = 55)

### Dilution Formula

As already mentioned above, the dilution formula is simply a derivitive of Ray Daniels formula modified to find our target gravity.

End Gravity = (Beginning Volume * Beginning Gravity) / End Volume

The above formula has been modified slightly to accommodate multiple additions to your starting wort volume.

To do this, we simply find our final volume from all 3 additions and then apply the above formula for each and combine them together to find the average gravity of wort after all 3 additions have been made.

To help illustrate how this modified formula is applied, Let’s run through a quick example using the default values from the above calculator.

Volume 1 Gravity = (3 * 70 gravity points) / 5
Volume 1 Gravity = 42

Volume 2 Gravity = ( 2 * 0) / 5
Volume 2 Gravity = 0

Volume 3 Gravity = (0 * 37) / 5
Volume 3 Gravity = 0

All we are doing with the above calculations is trying to find the weighted averaged for each addition.

From here, simply add the results together and then convert that number back to proper Specific Gravity format.

End Gravity = 42 + 0 + 0
End Gravity = (42 / 1000) + 1

End Gravity = 1.042

### Boil-Off Formula

The Boil-Off formula is used to calculate what your ending gravity will be after you boil it down to your target volume.

Ending Gravity = (Beginning Volume * Beginning Gravity Points) / End Volume

### Volume Change Formula

The volume change formula will calculate your target volume if you have a desired gravity  you are aiming for.

This formula and the calculator above can be applied for both water top-off and dilution scenarios.

New Volume = (Beginning Volume * Beginning Gravity Points) / Ending Gravity Points