ABV Calculator & Guide
Why accuracy matters: Alcohol calculation relies on the difference between your starting sugar density (OG) and your finishing density (FG). This tool helps you accurately determine your beer's strength, attenuation, and provides advanced corrections for temperature and refractometer use.
Alcohol By Volume Calculator
Enter your Original Gravity (OG) and Final Gravity (FG). Use Advanced if readings were taken warm or with a refractometer.
- Input your OG (Brew Day) and FG (Bottling Day).
- Select your units (SG is standard).
- Check the Results panel for ABV and Attenuation.
0.0% ABV
Tip: ABV is an estimate. For best accuracy, ensure your hydrometer is calibrated.
Advanced Configuration
If temps are left blank, the calculator assumes readings are already corrected to calibration temperature.
How can I increase the alcohol content of my beer?
"Adding sugar is easy. Adding sugar correctly is science."
Did you ever see the movie Men in Black? It featured the wonderful actor Vincent D'Onofrio as an angry alien that loved sugar. And lots of it. That is basically the simple answer to how to increase the alcohol content of your beer: You add sugar.
But you must do it with science. Adding sucrose (table sugar) or dextrose is easy, but the reality of fermentation science is nuanced. Simply dumping sugar into a fermenter changes the osmotic pressure on your yeast and alters the flavor profile. Like baking a cake, straying from the recipe can produce "hot" fusel alcohols (which give bad hangovers) or a thin, watery mouthfeel.
The Science of ABV: The Formula
Alcohol By Volume (ABV) represents the percentage of volume of alcohol per volume of beer. The standard formula for homebrewers to calculate the percentage of alcohol is:
You need to increase the Original Gravity (OG)—the amount of dissolved sugars before fermentation—while ensuring your yeast is healthy enough to bring the Final Gravity (FG) down.
What can I add to my beer kit?
To increase the OG, you need fermentables. Here is a basic ingredient list with their approximate gravity contributions:
- Dry Malt Extract (DME): Adds ~44 gravity points per pound. Adds body and alcohol. Preferred for quality.
- Liquid Malt Extract (LME): Adds ~36 gravity points per pound. Adds body and alcohol.
- Corn Sugar (Dextrose): Adds ~46 gravity points per pound. 100% fermentable. Lightens body.
- Table Sugar (Sucrose): Adds ~46 gravity points per pound. 100% fermentable.
- Honey: Adds ~35-42 gravity points per pound. Highly fermentable, adds distinct aromatics. See our guide on using honey in beer brewing.
- Brown Sugar: Adds ~46 gravity points. Adds slight molasses notes.
Using extra DME or LME (The Malt Approach)
Some brewers use extra dry malt extract as their sugar source. This is generally the preferred method for maintaining a high-quality beer. Unlike simple sugars, malt extract adds unfermentable dextrins, ensuring the beer retains a full body and "malty" mouthfeel to balance the alcohol.
The Math: In a 5-gallon batch, adding 1 lb (0.45kg) of DME adds approximately 0.009 to your specific gravity, translating to roughly 1% ABV increase.
Adding simple sugars (The Dextrose Method)
Using corn sugar or table sugar boosts ABV rapidly. However, yeast consumes simple sugars much easier than maltose. If you add too much, the yeast may become "lazy" and fail to consume the complex malt sugars, leaving you with a stalled fermentation. Furthermore, simple sugars ferment out completely, which can thin out the body. In high quantities, this leads to a "cidery" off-flavor.
The Golden Rule: Don't exceed 30% Adjuncts
It's widely recommended that no more than 1/3 (approx 30%) of your beer's total fermentables should come from non-malt adjuncts (sugar, honey, corn). If you exceed this, the beer will lack the proteins needed for head retention (foam) and may taste solvent-like.
Yeast Management: Osmotic Pressure
A big caution is that the more sugar you put in, the more pressure you place on the yeast. Osmotic Shock occurs when you pitch yeast into very sugary wort, drawing water out of the cells and stressing them.
To combat this, use Yeast Nutrients (like DAP or Fermaid K) to provide the Free Amino Nitrogen (FAN) that sugar lacks. For very high alcohol beers, consider Step Feeding: dissolving sugar in boiling water and adding it on Day 3 or 4 of fermentation, rather than all at once.
- Add extra DME for a balanced boost or Dextrose for a drier boost.
- Add Honey/Syrups 2-3 days into fermentation to preserve aromatics.
- Make a Yeast Starter to increase cell count.
- Use Yeast Nutrient to prevent stress.
- Keep temperature controlled to avoid "hot" fusel alcohol flavors.