Now and then I get asked about ABV vs Proof . What are they? How are they calculated? Since my reviews all contain a reference to the strength of the whiskey (usually %ABV), I thought I would write an explanation about each of them. ABV (Alcohol by Volume) and proof are both regional measurements of the alcohol content of whiskey.
- ABV (Alcohol by Volume): ABV is a standard measure of the amount of alcohol (ethanol) present in a whiskey as a percentage of the total volume. For example, if a whiskey has an ABV of 40%, it means that 40% of the total volume of the liquid is alcohol.
- Proof: Proof is a historical measurement of alcohol content that is still used in some countries, including the United States. In the United States, proof is calculated as twice the ABV percentage. In the UK and other countries, the proof system is different, and proof is calculated as 1.75 times the ABV percentage.
To convert between ABV and proof:
In the USA:
To convert ABV-Proof or Proof-ABV, multiply/divide the by 2.
In the UK/other country:
To convert ABV-Proof or Proof-ABV, multiply/divide by 1.75.
For example:
If a whiskey is: In the USA. In the UK
Whiskey 100 Proof 50% ABV 57% ABV
Whiskey 50% ABV. 100 Proof 88 Proof
This will only really matter if you are purchasing and travelling with Whiskey or ordering internationally as bottles sold in each of the countries must comply with labelling law if it exists.