To understand the numbers, you have to look at the production timeline.
In the United States, proof is exactly double the ABV (e.g., 40% ABV is 80 proof). In the historical British system, "100 proof" was roughly 57.06% ABV, though this was largely replaced by ABV in 1980. Evolution of Alcohol Strength During Production alcohol content in whisky
A standard 40% ABV whisky contains 40 ml of pure alcohol per 100 ml of liquid. A typical 25 ml pour equals 10 ml of pure alcohol. To understand the numbers, you have to look
Whisky’s alcohol content is typically measured as (Alcohol by Volume). Most bottled whiskies range from 40% to 50% ABV , though cask-strength expressions can reach 55–65% ABV or higher. Evolution of Alcohol Strength During Production A standard
Whisky typically has a minimum alcohol content of 40% alcohol by volume (ABV), though it can range as high as 68% or more for certain variations like cask strength. In most jurisdictions, including the EU and the United States, a spirit must contain at least 40% ABV to be legally classified and sold as "whisky". Foundational Concepts of Alcohol Content