Alcohol By Volume (ABV) Calculator

Alcohol by volume (ABV) is a measure of the strength of a drink, and indicates the percentage of pure alcohol in the total volume of the beverage. This calculator can be used in two ways:

If you are brewing something, by entering the starting and ending values measured with a hydrometer, it will calculate the ABV for that particular batch as well as apparent attenuation, calories and alcohol content (proof). If you know the ABV of a drink already, enter the volume to find out how many standard drinks this is equivalent to and how many grams of pure alcohol are contained.

What does alcohol by volume mean?

Alcohol by volume (ABV) is the measure of how much pure ethanol is present in a given volume of beverage at 20 °C. A beer with 5% ABV has 5% of its volume as pure alcohol, while a spirit with 40% ABV is a much stronger drink. This value is used on labels for alcoholic beverages all over the world, so you can compare light lagers, full-bodied red wines and small amounts of whiskey using the same scale.

Here's how to use this calculator:

Select the mode at the top. The "Gravity" mode is for brewers and requires entering the starting and ending gravity. The "Drink" mode is for those who want to estimate their alcohol consumption, and it requires entering the ABV on the label and how much was poured.

In the Density mode you can enter a value for density or Plato and switch between the standard formula and an alternative one. In the Beverage mode you can select which national standards to use for calculating alcohol content as definitions vary from region to region.

Alcohol by volume (ABV) calculation

During the fermentation process sugars are converted into alcohol so the difference between the density before and after fermentation indicates how much alcohol has been produced. The standard formula multiplies this difference by a fixed constant.

For everyday drinking beer, you can calculate the alcohol content quickly and accurately. For brewery products with higher alcohol content, the alternative formula proposed by Michael Hall better reflects actual conditions.

OG is the original gravity and FG is the final gravity, both of which are expressed as a density. For wine, another constant (136), instead of 131.25, can be used because of additional reduction in the density by yeast.

Example calculation

Assume the initial density is 1.050 and the final density is 1.010. The standard formula produces the following results:

This beer has an apparent attenuation of about 79%, and contains approximately 164 calories (per 12 ounce), making it a refreshing beverage that can be enjoyed in moderation.

Density and Plato degree

The density is a measure of how dense the wort is compared to water. The value for water is 1.000 while the value for malt that contains sugar will be higher, e.g. 1.050. Plato gives the same amount of sugar in weight percentage. So 1.050 corresponds to a value close to 12.4 Plato. Brewers measure these values with a hydrometer or refractometer. This calculator shows both scales so no manual conversion is needed.

ABW, alcohol content, apparent fermentation degree, calories

The alcohol by weight (ABW) is the percentage of alcohol in a drink by weight as opposed to volume. As alcohol is lighter than water, the ABW will always be lower than the ABV and is approximately equal to the ABV divided by 1.25.

Proof is a long-established scale for measuring the alcoholic strength of spirits. In the United States, proof equals twice the alcohol by volume (ABV), so that a distilled spirit with an ABV of 40% has a proof of 80. The British scale is about 1.75 times the ABV.

Apparent attenuation is the percentage of sugar that has been consumed by the yeast. The higher this number, the drier and more fermented the beer will be. Calories come from both alcohol and residual carbohydrates and are calculated based on a method used by brewers for a 12-ounce serving.

Number of standard drinks:

If you know the ABV and volume of a drink, then you can calculate how much pure alcohol it contains. Multiply the volume by the ABV to get the volume of ethanol, then multiply that by 0.789 to convert the volume of ethanol in milliliters into grams.

A standard drink contains a certain amount of pure alcohol, which varies from country to country. To work out the number of standard drinks, divide the number of grams of alcohol by your country's reference amount.

A beer of 12 ounces and 5% ABV contains about 14 grams of alcohol, which is the equivalent to a standard drink in the United States; the same beer would be the equivalent of approximately 1.8 units in the UK.

Tips to improve measurement accuracy:

The values of a hydrometer change with temperature. So make sure the sample is at the hydrometer's calibration temperature or correct for the readings accordingly. Take the final weight before adding sugar to carbonate. If the final weight is higher than the initial weight, this indicates that the density has decreased during fermentation which can lead to inaccurate measurements.

Symbols used:

This calculator is for general educational purposes and home brewing use only. It is not medical advice, the results are estimates, accuracy depends on correct reading and input of amounts used. Drink responsibly and follow your local alcohol guidelines.