Free tool
Proof Gallon Calculator
A proof gallon is one US liquid gallon of spirits at 100 proof (50% ABV). It is the unit the TTB uses for excise tax and operational reports. Enter wine gallons and proof to get proof gallons instantly.
The formula
proof gallons = wine gallons x (proof / 100)
27 CFR 30.36 (definition of proof gallon). This tool uses the same calculation as the Spirit Sight platform. It is general information, not tax or legal advice.
What is a proof gallon?
One US liquid gallon of spirits at 100 proof (50% alcohol by volume). It is the TTB unit for excise tax and reporting.
How do you calculate proof gallons?
Multiply wine gallons by the proof, then divide by 100. A 53-gallon barrel at 125 proof is 53 x 125 / 100 = 66.25 proof gallons.
Is a proof gallon the same as a wine gallon?
No. A wine gallon is a liquid gallon regardless of strength; a proof gallon adjusts for alcohol content (proof / 100).
See your distillery in Spirit Sight
Book a walkthrough with our team. We’ll show your operation - barrels, TTB, and the books - in one place.
Schedule a Demo