ABV Calculator
Calculate the alcohol by volume (ABV) of your homebrew from original and final gravity readings.
How to Use the ABV Calculator
- Measure the original gravity (OG) of your wort before fermentation.
- Measure the final gravity (FG) after fermentation is complete.
- Enter both values in the fields.
- Click Calculate to see the ABV percentage and attenuation.
Use Cases
- •Determining alcohol strength of homebrewed beer.
- •Calculating ABV of homemade wine or cider.
- •Verifying fermentation completion.
- •Label preparation for homebrew sharing.
Formula
ABV (%) = (Original Gravity − Final Gravity) × 131.25.
Frequently Asked Questions
How accurate is the ABV formula?
The simplified formula (OG−FG)×131.25 is accurate to within 0.2–0.3% ABV for most homebrew beers. For higher-gravity brews, use the extended formula.
Can I use this for wine or cider?
Yes. The same gravity-based formula applies to any fermented beverage measured with a hydrometer or refractometer.
What does apparent attenuation tell me?
Apparent attenuation shows what percentage of fermentable sugars were converted to alcohol. A typical ale yeast attenuates 70–80%.