Health & Fitness

ABV Calculator Alcohol by Volume

Original and final gravity

Calories per serving

Standard drinks count

Enter Gravity ReadingsFree · Instant

Original Gravity (OG)

Before fermentation (e.g. 1.040–1.080)

Final Gravity (FG)

After fermentation (e.g. 1.006–1.020)

Serving Size (fl oz)

How the ABV Calculator Works

ABV is calculated by measuring how much sugar yeast consumed during fermentation. You take a specific gravity reading before fermentation (OG) and one after it finishes (FG), then apply the formula below. The heavier the original wort and the drier the final beer, the higher the ABV.

Simple formula (beers under 10%):
  ABV = (OG - FG) × 131.25

Alternate formula (higher accuracy for strong beers):
  ABV = (76.08 × (OG - FG) / (1.775 - OG)) × (FG / 0.794)

Why 131.25?

The constant 131.25 comes from the density of ethanol and water. Each gravity point (0.001 SG units) represents roughly 0.131% ABV when fully fermented. The factor was empirically derived and is widely used across homebrewing and commercial applications.

Who Uses This Calculator?

Homebrewers

Verify your batch's ABV and confirm fermentation is complete before bottling.

Craft beer makers

Track gravity readings to hit target ABV in recipes and label beverages accurately.

Wine and cider makers

Apply the same gravity formula to wines and ciders to calculate alcohol content.

People watching intake

Know exactly how many standard drinks are in a homebrew pint before you pour a second one.

How to Use the Calculator

1
Measure original gravity before pitching yeast
Use a hydrometer or refractometer on your cooled wort before adding yeast. Record the number (e.g. 1.052). This is your OG.
2
Measure final gravity after fermentation
Once fermentation appears complete and no bubbling occurs for 48 hours, take a final reading. Most beers finish between 1.006 and 1.018.
3
Enter both readings above
Type OG and FG into the fields. OG must be greater than FG, otherwise the yeast has not fermented the wort.
4
Enter your serving size
Enter the number of fluid ounces in your serving. A standard pint is 16 oz, a standard bottle is 12 oz.
5
Read your results
The calculator shows ABV, approximate calorie count per serving, and how many US standard drinks that serving represents.

Example Calculation

Derek brewed an American IPA. His OG reading was 1.065 and his final gravity after two weeks was 1.012. He is pouring 16 oz pints.

OG1.065
FG1.012
ABV = (1.065 - 1.012) x 131.25= 6.96%
Calories (16 oz pint)~237 kcal
Standard drinks (16 oz)~2.20 drinks

Common Mistakes to Avoid

Taking FG before fermentation finishes

If your FG reading is unstable over 48 hours, fermentation is still active. Taking the reading too early gives a falsely high ABV estimate and may mean your beer is not ready to bottle.

Not calibrating your hydrometer for temperature

Most hydrometers are calibrated at 60°F (15.5°C). Measuring warm wort gives a higher-than-actual gravity reading. Use your hydrometer's temperature correction chart or let the sample cool first.

Entering Plato or Brix instead of specific gravity

This calculator uses specific gravity (1.000 scale). If your refractometer reads in Brix, convert using: SG = 1 + (Brix / (258.6 - (Brix / 258.2) x 227.1)). A Brix reading of 13 equals roughly 1.053 SG.

Using refractometer for FG without correction

Refractometers become inaccurate after fermentation because alcohol bends light differently. Use a hydrometer for your final gravity reading, not a refractometer, unless you apply the alcohol correction factor.

Confusing ABV with ABW (alcohol by weight)

Some countries and keg specifications use ABW (alcohol by weight). ABV is always higher than ABW. To convert: ABW = ABV x 0.789. A 5% ABV beer is approximately 3.95% ABW.

Frequently Asked Questions

ABV (Alcohol by Volume) is the percentage of a beverage's total volume that is pure ethanol. Commercial breweries measure it using lab equipment. Homebrewers use a hydrometer to measure original gravity (OG) before fermentation and final gravity (FG) after, then apply the formula ABV = (OG - FG) x 131.25.

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Sources & References

Brewer's Association: Beer Style Guidelines 2024

ABV ranges for all recognized beer styles, used as reference for the style classification in results.

U.S. NIAAA: What is a Standard Drink?

Source for the 0.6 fl oz (14 grams) pure ethanol definition of one standard drink used in this calculator.

Palmer, J.J. (2017): How to Brew, 4th Edition

Source for the simple and alternate ABV formulas, specific gravity measurement methods, and temperature correction guidance.

Tom Reyes

Certified beer judge (BJCP), homebrewer of 12 years, contributor to homebrewing publications

Tom reviewed the ABV formulas, gravity measurement guidance, and standard drink calculations on this page. He has evaluated over 400 homebrewing entries at regional and national competitions.

Reviewed: April 2025Last updated: April 2025

Typical Gravity Ranges

Style	OG	ABV
Session Ale	1.028-1.040	2.8-4%
American Lager	1.040-1.050	4-5%
Pale Ale / IPA	1.050-1.070	5-7.5%
Belgian Strong	1.070-1.095	7-10%
Barleywine	1.100-1.120	10-13%

US Standard Drink Reference

Regular beer (12 oz) (5%)1.0 std

Craft IPA (12 oz) (7%)1.4 std

Table wine (5 oz) (12%)1.0 std

Spirits (1.5 oz) (40%)1.0 std

Pro Tip

Take two identical FG readings 48 hours apart. If they match, fermentation is complete. If they differ by more than 0.002, wait another two days before taking your official final reading.

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