An ABV calculator determines the alcohol content of your homebrew by comparing the gravity of your wort before and after fermentation. By entering your Original Gravity (OG) and Final Gravity (FG) readings from a hydrometer or refractometer, you can instantly calculate the alcohol by volume percentage, apparent attenuation, and estimated calories per serving.
Gravity Readings
Before fermentation (1.000 - 1.200)
After fermentation (0.990 - 1.100)
Common Beer Styles — OG / FG Reference
| Style | OG Range | FG Range | ABV Range |
|---|---|---|---|
| Light Lager | 1.028 - 1.040 | 0.998 - 1.008 | 2.8 - 4.2% |
| Wheat Beer | 1.044 - 1.052 | 1.008 - 1.014 | 4.3 - 5.6% |
| Pale Ale | 1.044 - 1.060 | 1.008 - 1.014 | 4.4 - 6.2% |
| IPA | 1.056 - 1.075 | 1.008 - 1.016 | 5.5 - 7.5% |
| Amber / Red Ale | 1.045 - 1.060 | 1.010 - 1.015 | 4.5 - 6.0% |
| Brown Ale | 1.040 - 1.052 | 1.008 - 1.013 | 4.2 - 5.4% |
| Porter | 1.040 - 1.058 | 1.008 - 1.016 | 4.0 - 5.5% |
| Stout | 1.036 - 1.056 | 1.008 - 1.016 | 4.0 - 5.5% |
| Belgian Tripel | 1.075 - 1.085 | 1.008 - 1.014 | 7.5 - 9.5% |
| Imperial Stout | 1.075 - 1.115 | 1.012 - 1.024 | 8.0 - 12.0% |
| Barleywine | 1.080 - 1.120 | 1.016 - 1.030 | 8.0 - 12.0% |
How to Use the ABV Calculator
Knowing the alcohol content of your homebrew is essential for recipe development, legal labelling, and responsible enjoyment. This free ABV calculator takes your hydrometer or refractometer gravity readings and instantly returns the alcohol by volume, apparent attenuation, and estimated calories so you can evaluate your brew without any manual maths.
Step 1: Take your gravity readings
Use a hydrometer or refractometer to measure the Original Gravity (OG) of your wort before pitching yeast and the Final Gravity (FG) once fermentation is complete. OG values typically range from 1.030 for a light session beer up to 1.120 for a barleywine. FG usually falls between 0.998 and 1.020, depending on yeast attenuation and residual sugars.
Step 2: Enter values and calculate
Type your OG and FG into the input fields and click Calculate ABV. The calculator runs two formulas side by side: the simple formula (OG - FG) × 131.25, which is a quick approximation, and an advanced formula that is more accurate for stronger beers above 6% ABV. Both results are displayed so you can compare.
Step 3: Use temperature correction (optional)
Hydrometers are calibrated at a specific temperature, often 60 °F or 68 °F. If you took your reading at a different temperature, enable the temperature correction toggle and enter both the sample temperature and your hydrometer's calibration temperature. The calculator adjusts the gravity values before computing ABV, giving you a more precise result.
Step 4: Review your results
In addition to ABV, the results panel shows apparent attenuation (how efficiently the yeast consumed sugars), estimated calories per 12 oz serving, and the gravity values converted to degrees Plato. A style suggestion helps you see where your beer falls among common styles.
Step 5: Use the reference table
Scroll down to the OG/FG reference table for common beer styles. This is useful when planning a new recipe: pick a target style, note the typical gravity range, and use those values as your starting point for grain bill calculations. Compare your finished beer's numbers against the style guidelines to see how close you landed.
All calculations happen instantly in your browser. No data leaves your device, and you can bookmark this page to use the ABV calculator anytime you brew.
FAQ
Is this ABV calculator really free?
Yes, the ABV calculator is completely free with no limits and no account required. Use it as often as you like. All calculations happen in your browser -- nothing is stored or sent anywhere.
Is my data safe and private?
Absolutely. Every calculation runs entirely in your browser using JavaScript. No data is sent to any server, stored in any database, or shared with anyone. You can even use the tool offline once the page has loaded.
What is the difference between the simple and advanced ABV formulas?
The simple formula (OG - FG) x 131.25 is a quick approximation that works well for most beers under 6% ABV. The advanced formula accounts for the non-linear relationship between gravity and alcohol at higher concentrations, making it more accurate for strong beers, barleywines, and imperial stouts.
What are Original Gravity and Final Gravity?
Original Gravity (OG) measures the sugar content of your wort before fermentation, typically between 1.030 and 1.120. Final Gravity (FG) measures the sugar remaining after fermentation, usually between 1.000 and 1.020. The difference tells you how much sugar was converted to alcohol.
What is apparent attenuation and why does it matter?
Apparent attenuation is the percentage of sugars that yeast consumed during fermentation. Most ale yeasts attenuate between 70-80%. Low attenuation means a sweeter, fuller-bodied beer, while high attenuation produces a drier, thinner beer. It helps you evaluate your yeast's performance.
Do I need to correct my hydrometer reading for temperature?
Hydrometers are calibrated at a specific temperature, usually 60 F (15.6 C) or 68 F (20 C). If your sample is warmer or cooler, the reading will be slightly off. Enable the temperature correction toggle for more accurate results, especially if your sample temperature differs significantly from the calibration temperature.
How accurate is the calorie estimate?
The calorie estimate uses a widely accepted formula from the brewing industry that accounts for both alcohol calories and residual carbohydrate calories. It gives a good approximation for a standard 12 oz (355 ml) serving, though actual values may vary slightly depending on your specific ingredients and process.