Homebrew ABV Calculator
Quickly calculate the alcohol content of your homebrew using original and final gravity readings. Get instant insights into ABV, attenuation, and calories so you can better understand and refine every batch.
Standard works fine up to ~8% ABV. Switch to Accurate (Hall) for big beers where the simple formula starts to drift.
Correct readings taken at a different temperature than your hydrometer's calibration.
Alcohol by volume — the percentage of your finished beer that's ethanol. A 5% beer is 5% alcohol and 95% everything else.
We measure sugar density before fermentation (OG) and after (FG). The gap between them tells us how much sugar the yeast converted to alcohol and CO₂.
Hydrometers are cheap, accurate, and need a large sample. Refractometers use a single drop and read any temperature — but they read FG incorrectly once alcohol is present. This calculator corrects for that.
Read the bottom of the meniscus, not the top. Correct for temperature if your sample isn't at calibration temp. Confirm FG with two stable readings 2–3 days apart before packaging.
Understand Your Beer—Beyond the Recipe
Alcohol by volume (ABV) is one of the most important metrics in homebrewing. It tells you how strong your beer is, how fermentation performed, and how your recipe balances flavor and body.
By comparing your Original Gravity (OG) and Final Gravity (FG), this calculator shows how much sugar was converted into alcohol during fermentation—giving you a clear picture of your brew’s outcome.
If you’re still building your recipe, try our <a href="/pages/recipe-builder">Beer Recipe Builder</a> to design your beer from the ground up.
What is ABV?
ABV (Alcohol by Volume) is the percentage of alcohol in your finished beer. During fermentation, yeast consumes sugars and produces alcohol and CO₂. The more sugar converted, the higher the ABV.
- Lower ABV (3–5%) = lighter, more sessionable beers
- Mid-range ABV (5–7%) = balanced, everyday craft styles
- Higher ABV (7%+) = stronger, more complex beers
How ABV is Calculated
ABV is determined using your gravity readings before and after fermentation:
- Original Gravity (OG): Sugar content before fermentation
- Final Gravity (FG): Remaining sugar after fermentation
The difference between these values tells you how much sugar was converted into alcohol.
Standard Formula:
ABV = (OG − FG) × 131.25
Most brewers use this formula as a reliable estimate for typical beer styles.
Hydrometer vs. Refractometer
You can measure gravity using either tool:
Hydrometer:
- Most common and beginner-friendly
- Highly accurate with proper temperature correction
Refractometer:
- Requires only a small sample
- Needs correction after fermentation due to alcohol presence
Want to upgrade your setup? Browse our brewing equipment for hydrometers, refractometers, and more.
Why ABV Matters
Understanding your ABV helps you:
- Dial in recipe balance (sweetness vs dryness)
- Monitor fermentation performance
- Replicate successful batches
- Stay consistent across brews
It’s also a key indicator of how much sugar your yeast consumed—known as attenuation—which impacts both flavor and mouthfeel.
Common Mistakes to Avoid
- Taking FG readings too early (wait until stable for 2–3 days)
- Not correcting for temperature when using a hydrometer
- Reading the top of the meniscus instead of the bottom
- Forgetting refractometer correction after fermentation
If you're just getting started, our homebrewing guides walk through every step in detail.
Take Your Brewing Further
Once you know your ABV, you can start refining your recipes for better results:
- Build and customize recipes with our Recipe Builder
- Explore proven styles with our beer recipe kits
- Experiment with new flavors using premium ingredients
Ready for Your Next Batch?
Use your results to tweak your next brew, improve consistency, and create beers that are exactly how you like them.
