ABV Calculator

Calculate alcohol by volume with accurate brewing formulas.

How to Use the ABV Calculator

An ABV (Alcohol by Volume) calculator helps you figure out how strong your beer, wine, or other fermented drink is. It works by comparing two important measurements taken during the brewing process: Original Gravity (OG) and Final Gravity (FG).

Original Gravity (OG) is measured before fermentation starts. It tells you how much sugar is in your liquid (called wort). The more sugar there is, the more potential alcohol your drink can produce.

Final Gravity (FG) is measured after fermentation is finished. During fermentation, yeast consumes sugar and turns it into alcohol and carbon dioxide. Because sugar is heavier than alcohol, the liquid becomes less dense over time, which is why FG is lower than OG.

The calculator uses the difference between OG and FG to estimate how much sugar was converted into alcohol. The bigger the difference, the stronger the drink.

There are two main formulas used:

  • The standard formula is simple and quick. It multiplies the difference between OG and FG by a constant. This works well for most homebrewers.
  • The advanced formula is more precise. It adjusts for the fact that alcohol is less dense than water and gives more accurate results, especially for stronger beers.

The calculator can also work with two measurement systems:

  • Specific Gravity (SG) – commonly used in the US (values like 1.050)
  • Plato (°P) – commonly used in Europe (values like 12°P)

If you enter values in Plato, the calculator automatically converts them to Specific Gravity behind the scenes so the formulas still work correctly.

Besides ABV, the calculator can also estimate:

  • Apparent Attenuation – how much sugar was consumed by yeast
  • Calories – based on both alcohol and leftover sugars
  • Real Extract – a more scientific measure of remaining sugars

In simple terms, this tool takes your “before” and “after” readings and turns them into useful insights about your drink’s strength, taste, and body. It removes guesswork and helps you brew more consistent and predictable results.