ABV Calculator: Alcohol by Volume for Beer, Wine and Cider
Enter your original gravity (OG) and final gravity (FG) readings to calculate the ABV of your homebrew beer, wine, mead, or cider. You also get apparent attenuation, US proof, UK proof, alcohol by weight, and estimated calories per 12 oz serving. Switch between specific gravity and degrees Plato, and choose between the standard formula and the more accurate alternate formula.
What ABV means and why it matters
Alcohol by volume (ABV) is the standard measure of how much pure ethanol is in a beverage, expressed as a percentage of total volume. A beer labeled 5.0% ABV contains 5 mL of pure ethanol per 100 mL of liquid. The figure is set by law in most countries and must appear on commercially sold beverages. For homebrewers, ABV is calculated from the drop in gravity between the start and end of fermentation: yeast consumes sugar and produces ethanol and carbon dioxide, so the liquid becomes denser than water (high OG) then lighter than water (low FG).
Original gravity, final gravity, and how the formula works
Specific gravity is the ratio of your liquid's density to pure water at the same temperature. Water is 1.000; a wort with lots of dissolved sugar might read 1.052. After fermentation, the yeast has eaten most of the sugar and the gravity drops, typically to between 1.005 and 1.020 depending on yeast strain and recipe. The standard formula, ABV = (OG - FG) x 131.25, is a simplified version derived from the full ASBC equation and is accurate to within about 0.2% ABV for most beers. The alternate formula, ABV = (76.08 x (OG - FG) / (1.775 - OG)) x (FG / 0.794), corrects for the non-linearity of the relationship at higher gravities and is recommended for beers above OG 1.080. Apparent attenuation tells you what fraction of the original extract the yeast fermented: a result below 65% can indicate a stuck fermentation or a low-attenuation yeast strain, while above 85% suggests a very fermentable wort or a highly attenuative strain such as many dry-hop or kveik yeasts.
Specific gravity vs degrees Plato
Both units measure the same thing, the concentration of dissolved solids in wort, but use different scales. Specific gravity reads the ratio to water directly (1.050 means 5% denser than water). Degrees Plato expresses the same concentration as the equivalent mass of pure sucrose per 100 g of solution, so 1.050 SG corresponds to about 12.4 degrees Plato. Professional breweries worldwide use Plato because it scales linearly and pairs naturally with mass-based process measurements. Homebrewers in the US commonly use SG because most inexpensive hydrometers are graduated that way. This calculator accepts either and converts internally for all outputs.
Proof, alcohol by weight, and calories
US proof is simply twice the ABV: 40% ABV spirits are 80 proof. UK proof (degrees Sikes) equals ABV multiplied by 1.75 and dates to a gunpowder test used by excise officers in the 18th century. Alcohol by weight (ABW) is the mass of ethanol as a fraction of total beverage mass. Because ethanol (density 0.789 g/mL) is lighter than water, ABW is always lower than ABV by roughly 20% at typical beer strengths. ABW = ABV x 0.789 / FG density. Calorie estimates use the American Society of Brewing Chemists approach: ethanol provides about 7.1 kcal per gram, plus additional calories from residual fermentable and non-fermentable carbohydrates captured by the final gravity. A standard 5% lager delivers roughly 140-150 kcal per 12 oz; a 10% imperial stout can top 300 kcal.
Typical ABV ranges by beverage style
| Beverage / Style | Typical OG | Typical FG | ABV range | Category |
|---|---|---|---|---|
| Session ale / low-alcohol beer | 1.028-1.040 | 1.006-1.010 | 2.8-4.0% | Session |
| American lager / light beer | 1.036-1.048 | 1.006-1.010 | 3.5-5.0% | Standard |
| Pale ale / amber ale | 1.048-1.056 | 1.010-1.014 | 4.5-5.5% | Standard |
| India Pale Ale (IPA) | 1.056-1.075 | 1.008-1.016 | 5.5-7.5% | Strong |
| Wheat beer / Hefeweizen | 1.044-1.052 | 1.010-1.014 | 4.0-5.5% | Standard |
| Stout / Porter | 1.040-1.080 | 1.010-1.020 | 4.0-8.0% | Standard-Strong |
| Belgian Tripel | 1.075-1.095 | 1.008-1.014 | 7.5-9.5% | Strong |
| Imperial Stout / Barleywine | 1.090-1.120 | 1.014-1.030 | 8.0-12.0% | Very Strong |
| Dry table wine | 1.090-1.105 | 0.993-1.000 | 11.0-13.5% | Very Strong |
| Mead (traditional) | 1.080-1.130 | 0.990-1.010 | 8.0-18.0% | Strong-Very Strong |
| Hard cider | 1.045-1.065 | 0.998-1.005 | 4.5-7.0% | Standard-Strong |
Common hydrometer reading ranges and expected ABV for popular beer, wine, and other fermented beverages.
Frequently asked questions
What is a good OG and FG for a typical home-brewed pale ale?
Most American pale ales target an original gravity of 1.048 to 1.056 and a final gravity of 1.010 to 1.014, which puts the ABV between about 4.5% and 5.5%. A gravity of 1.052 OG dropping to 1.012 FG works out to about 5.2% ABV using the standard formula.
Which formula should I use, standard or alternate?
For most beers with an OG below 1.075, the standard formula (OG - FG) x 131.25 is accurate enough for all practical purposes. The alternate formula matters mainly for high-gravity beers, barleywines, and wines where the standard formula can underestimate ABV by 0.2 to 0.5%.
My FG is higher than expected. Did fermentation stall?
Possibly. Take a reading again 48-72 hours later: if the gravity has not changed, fermentation is complete for better or worse. A stable but high FG can mean the yeast ran out of nutrients, the temperature dropped too low, or the wort had a high proportion of unfermentable dextrins. If the reading is still dropping, wait longer and keep the temperature in the yeast's optimal range.
How do I convert specific gravity to degrees Plato?
Use the DeClerk polynomial: Plato = -616.868 + 1111.14 x SG - 630.272 x SG^2 + 135.997 x SG^3. In practice, the simple approximation Plato = (SG - 1) x 1000 / 4 is close enough for most brewing decisions (e.g. 1.052 SG = about 13 Plato). This calculator handles the conversion precisely in both directions.
What is apparent attenuation?
Apparent attenuation is (OE - AE) / OE expressed as a percentage, where OE is original extract and AE is apparent extract in degrees Plato. It measures how much of the original fermentable sugar the yeast consumed. "Apparent" refers to the fact that the ethanol produced by fermentation is lighter than the sugars it replaced, so a hydrometer slightly overstates attenuation. Real attenuation corrects for this but requires additional calculations. For most brewing decisions, apparent attenuation is sufficient.
How many standard drinks is my homebrew?
One standard drink in the US contains 14 g of pure ethanol, which is 17.7 mL or about 0.6 fl oz. Divide the pure alcohol volume in your batch (shown as "total alcohol in batch" above) by 0.6 to get the total standard drinks. For a single serving, multiply 12 oz by your ABV fraction and divide by 0.6. A 12 oz beer at 5% ABV equals 0.6 fl oz of alcohol, which is exactly one standard drink.
Does temperature affect my hydrometer reading?
Yes. Hydrometers are calibrated to a reference temperature, usually 60 degrees F (15.6 C) or 68 degrees F (20 C). At higher temperatures the liquid is less dense, so your reading will be lower than the true gravity. Use a hydrometer temperature correction calculator to adjust readings taken above or below the calibration temperature. For an accurate final gravity, always let the sample cool to room temperature before reading.