What is Alcohol By Volume (ABV)?
Alcohol By Volume (ABV) is the standard measurement used worldwide to quantify the amount of alcohol (ethanol) contained within an alcoholic beverage. It represents the percentage of the total volume of the liquid that is pure alcohol.
How to Measure Gravity
To use this calculator, you need two measurements taken with a hydrometer or refractometer:
- Original Gravity (OG): The specific gravity of the unfermented liquid (wort or must) before yeast is pitched.
- Final Gravity (FG): The specific gravity of the fermented liquid after fermentation has completely finished.
The difference between these two numbers indicates how much sugar was consumed by the yeast and converted into alcohol and CO2.
Standard vs. Alternate Equation
This tool offers two equations to calculate ABV:
- Standard Equation:
ABV = (OG - FG) * 131.25
This is the most common formula used by homebrewers. It is simple and highly accurate for most beers under 6% ABV. - Alternate Equation:
ABV = (76.08 * (OG - FG) / (1.775 - OG)) * (FG / 0.794)
This more complex formula accounts for the changing density of the liquid as alcohol is produced. It is recommended for high-gravity beers, meads, and wines (generally anything above 6-7% ABV) where the standard equation begins to lose accuracy.