Original specific gravity
Final specific gravity
ABV (alcohol by volume)
ABW (alcohol by weight)
Proof (UK)
Proof (US)
Alcohol content
Total volume

If you want to calculate the alcohol content of your homebrew beer, this ABV calculator (alcohol by volume calculator) is a perfect tool for you. It will help you estimate the percentage of alcohol in any liquor basing on its initial and final specific gravity. In the article below, you can read about what is alcohol, alcohol facts, myths about alcohol and history of alcohol. Moreover, you can find information about calculating ABV from specific gravity and discover the alcohol formula. Use this beer ABV calculator wisely, and try not to fall into addiction! :)

What is alcohol by volume?

ABV is an abbreviation for alcohol by volume. This unit is a standard measure of how much of alcohol (ethanol) is contained in a given volume of an alcoholic beverage. It is expressed as a volume percent. By definition, this is the number of milliliters (mL) of pure ethanol present in 100 mL of solution at 20°C (68°F). The ABV standard is commonly used worldwide. In some countries, e.g. France, the term alcohol by volume is often replaced by degrees Gay-Lussac (thanks to the French chemist Joseph Louis Gay-Loussac). These two scales differ slightly: Gay-Lussac uses the value of 15°C (59 °F) for temperature (instead of 20°C).

Calculating ABV from specific gravity

The standard method of estimating ABV is to use the specific gravity. Specific gravity is the relative density of a liquid compared with the density of water. When fermentation occurs, the specific gravity of a spirit changes. You can monitor this change to find the alcohol content of your homebrew.

All formulas for finding the ABV are approximate, as they are found empirically rather than derived. You should always expect some error when using the alcohol calculator. The most popular equation is:

ABV = (OG - FG) * 131.25


  • ABV is the alcohol by volume, measured in percents;
  • OG is the original specific gravity (before fermentation), measured with a hydrometer;
  • FG is the final specific gravity (after fermentation).

You can also use this specific gravity calculator to recalculate this result into alcohol by weight. All you have to do is apply the following formula:

ABV = ABW / (0.789 + 0.211 * ABW)

The last thing our beer calculator does is finding the exact amount of alcohol in a given volume of alcoholic beverage. For example, you can determine the volume of alcohol in a 500 ml bottle of 4.5% beer. If you are interested in finding this value, use this equation:

alcohol volume = total volume * ABV

Difference between ABV, ABW and proof

Proof is a different measure of an alcoholic beverage. Its origins date back to 16th century England, where liquors were taxed basing on their alcohol content. They were tested in the following way: a pellet of gunpowder was soaked in a spirit, and if it could still burn afterwards, the spirit was deemed above proof and taxed higher than ordinary.

In 1816, the gunpowder test was replaced with specific gravity test. Since then, the main measure of alcohol content was ABV (alcohol by volume) or ABW (alcohol by weight). Still, you can find the equivalent of proof in ABV:

  • In the US, 'proof' is equal to twice the measure in ABV. For example, alcohol that is 100 proof has 50% ABV.
  • In the UK, proof is defined as follows: "a quantity of 100 degrees proof liquor has the same weight as 12/13 of the same volume of pure water at 51°F." Hence, 100 proof alcohol has 57.15% ABV.

Using our alcohol by volume calculator: an example

Let's assume you are brewing your own beer. What do you need to do to determine the volume of alcohol in one 330 ml bottle?

  1. Begin with calibrating your hydrometer. Check whether its reading for clear water is equal to 1. If not, you will have to adjust all consecutive readings.

  2. Take a hydrometer reading of your homebrew before fermentation begins. Let's assume this value - the original specific density - is equal to 1.060.

  3. Take a second hydrometer reading when your beer will be ready to drink. In this example we will assume the final specific gravity equal to 1.015.

  4. Input these values into the ABV formula:

ABV = (OG - FG) * 131.25 % = (1.060 - 1.015) * 131.25 % = 0.045 * 131.25 % = 5.91 %

  1. Once you have calculated the ABV, you can find the volume of alcohol in your beer by multiplying it by the total volume of homebrew in a bottle:

5.91% * 330 = 19.5 ml.

What is alcohol?

Alcohol (ethanol or ethyl alcohol) is the ingredient found in a beer, wine, vodka, and spirits. Our feelings after drinking are determined by the concentration of this small chemical molecule in our body. Consumed in reasonable amounts, they cause pleasure, while in excessive volume - drunkenness. Alcohol is formed when yeast ferments (breaks down without oxygen) the sugars in different food. For example, wine is made from the sugar in grapes, beer from the sugar in malted barley, cider from the sugar in apples, and vodka from the sugar in potatoes, barley, or other plants. Fermented drinks (beer or wine) contain from 2% to 20% of alcohol. Distilled drinks or liquors contain from 40% to 50% (or even more) of alcohol. The usual alcohol content for each is:

  • Beer 2-6% of alcohol
  • Cider 4-8% of alcohol
  • Wine 8-20% of alcohol
  • Tequila 40% of alcohol
  • Rum 40% and more of alcohol
  • Brandy 40% and more of alcohol
  • Gin 40-47% of alcohol
  • Whiskey 40-50% of alcohol
  • Vodka 40-50% of alcohol
  • Liqueurs 15-60% of alcohol

Alcohol is classified as a sedative hypnotic drug. It means that it acts to depress the central nervous system at high doses. On the other hand, in lower doses, it can acts as a stimulant, by inducing feelings of euphoria and increasing talkativeness. Keep in mind that alcohol overdose may lead to drowsiness, respiratory depression (slow and shallow breath, that can stop entirely), coma, or even death. In fact, alcohol has negative effects on every organ in the body. These effect depend on the blood alcohol concentration (BAC) over time.

Alcohol formula

From the chemical point of view, alcohol is an organic compounds. It is characterized by one or more hydroxyl (-OH) groups, which are attached to a carbon atom of an alkyl group. Alcohols may be considered as organic derivatives of water (H₂O) in which one of the hydrogen atoms has been replaced by an alkyl group. For example, in ethanol (or ethyl alcohol) the alkyl group is the ethyl group, −CH₂CH₃.

Alcohols are among the most common organic compounds. They are used e.g. as sweeteners and in perfume production. Probably the two best-known alcohols are ethanol and methanol. The first one is commonly used for the production of toiletries, pharmaceuticals, fuels and of course alcoholic beverages. The second one is used as a raw material for the manufacture of formaldehyde and special resins, in special fuels, antifreeze and cleaning materials.

Alcohol facts

Take a look at a few curious facts associated with alcohol and drinking.

  1. It only takes 6 minutes for brain cells to react to alcohol.

  2. The only type of alcohol that humans can drink without causing serious damage to the organism is ethanol or ethyl alcohol. They are widely used in beverages such as wine, beer, spirits etc.

  3. Alcohol is among the most commonly misused addictive substances. About 13% of American adults meet the criteria for alcohol use disorder (AUD). That is 1 in 8 adults!

  4. Alcohol can cause a wide variety of effects. It triggers the release of dopamine - a neurotransmitter that is associated with pleasure and satisfaction.

  5. According to the 2015 National Survey on Drug Use and Health, 86.4% of adults they have drunk alcohol at some point in their lifetime.

  6. Alcohol is a depressant. This means that it slows down the activity of the brain.

  7. Alcohol is processed in the liver, where enzymes help break down ethanol into acetaldehyde and acetate.

  8. Men are more likely to use alcohol than women.

  9. Women who are dependent on alcohol are 50-100% more likely to die from alcohol-related causes than men who are addicted to alcohol.

  10. Archaeologists found evidence suggesting that builders of Great Pyramids of Giza were paid in beer.

  11. The effects caused by drinking occur when ethanol enters your bloodstream and passes through the membranes of cells in your brain, heart and other organs.

  12. Stress relief is another side effect of alcohol drinking. This is caused by an increase in the uptake of the neurotransmitter called GABA.

Myths about alcohol

After reading about alcohol facts, let's now bust a few myths that the vast majority still believes in. You might be really surprised...

  1. Wine or beer won't make you as drunk as high volume alcohol. The truth: all types of alcohol contain the same active ingredient which makes us dizzy. It depends how much of that particular substance you consume during one sitting.

  2. Drinking is not a problem as long as you can hold your glass. The truth: being able to drink without feeling the effects could be a sign that you are developing alcohol tolerance. Over time, regular alcohol use can lead you to risk for AUD.

  3. Drinking with moderation is always safe. The truth: moderate alcohol consumption may have some health benefits, but it doesn't mean you can do it always without risk. In some situations you must not drink - e.g. while being pregnant or having a liver/pancreatic disease.

  4. Drinking alcohol of unknown origin is safe because alcohol inside is always the same. The truth: homemade or unknown-made alcohol may include contaminated alcohol or even toxic types of alcohol like methanol. You can die after drinking it.

  5. A cup of coffee will help you sober up. The truth: coffee contains caffeine which makes you feel more alert and awake. It doesn't help your body process alcohol faster.

History of alcohol

For thousands of years, people have used fermented grain, fruit juice, and honey to make alcohol. Fermented beverages existed in early Egypt and in China (there is evidence of an early alcoholic drink from 7000 B.C.) In India, an alcoholic beverage called 'sura' (distilled from rice) was in use between 3000 - 2000 B.C.

Several Native American civilizations developed alcoholic beverages in pre-Columbian times. In the Andes region in South America, lots of fermented beverages called 'chicha' was created from corn, grapes or apples.

In the sixteen century, alcohol called 'spirits' was largely used for medical purposes. In the mid-eighteenth century in Britan, gin consumption reached 18 million gallons and alcoholism became widespread. The nineteenth century brought a change in attitudes and the temperance movement began promoting the moderate use of alcohol. That was finally a push for total prohibition.

In 1920 the US passed a law prohibiting the manufacture, sale, import, and export of intoxicating liquors. The illegal alcohol trade boomed, and by 1933, the prohibition of alcohol was canceled. Today, estimation shows that 15 million Americans suffer from alcoholism and 40% of all car accident deaths in the US involve alcohol.

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