ganak.appABV Calculator
Free ABV calculator for beer, wine, mead, and cocktails. Calculate alcohol by volume from OG and FG gravity readings in SG, Plato, or Brix. Includes cocktail ABV mixer, ABV to Proof converter, attenuation, calories per serving, and standard drink count. Supports both simple and alternate (high-gravity) formulas.
Measure OG before fermentation and FG after. Use a hydrometer or refractometer.
5.25%
Alternate formula: 5.34% ABV
Fermentation Summary
Key metrics from your gravity readings
ABW
4.12%
US Proof
10.5
Apparent Atten.
79.3%
Calories/12 oz
163 kcal
Gravity in All Units
Your OG and FG converted to SG, Plato, and Brix
Extract & Attenuation
Sugar conversion details
OE
12.4°P
AE
2.6°P
RE
4.3°P
OE = Original Extract, AE = Apparent Extract, RE = Real Extract (Balling formula). Real attenuation accounts for the lower density of alcohol vs water.
What Is ABV (Alcohol by Volume)?
The universal measure of alcohol strength
Alcohol by Volume (ABV) measures the percentage of pure ethanol in a given volume of liquid. An ABV of 5% means that 5 ml of every 100 ml is pure alcohol. It is the international standard for labeling alcoholic beverages and is used by homebrewers, winemakers, and bartenders worldwide.
For fermented beverages (beer, wine, mead, cider), ABV is determined by comparing gravity readings before and after fermentation. The drop in gravity corresponds to the sugar consumed by yeast and converted into alcohol and CO₂.
3–12%
Beer
Most ales and lagers
9–16%
Wine
Table wine range
40%+
Spirits
Distilled liquor
ABV Formulas Explained
Two industry-standard calculation methods
Simple Formula (Papazian)
ABV = (OG − FG) × 131.25
Accurate for beers up to ~6% ABV. Quick and easy for most homebrew.
Alternate Formula (More Accurate)
ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794)
More accurate for high-gravity beers, wines, and meads above 6% ABV.
Both formulas use specific gravity (SG) values. The simple formula is a linear approximation that works well for most beers. The alternate formula accounts for the non-linear relationship between gravity drop and alcohol production at higher concentrations.
How to Measure Gravity
Getting accurate OG and FG readings
1. Hydrometer
Float the hydrometer in a sample at the calibration temperature (usually 60°F / 15.5°C). Read the scale at the meniscus (bottom of the liquid surface). Most affordable and reliable method.
2. Refractometer
Place a few drops on the prism and read the Brix scale. Works great for OG, but FG readings with alcohol present need a correction factor (the calculator handles this automatically).
3. Before Fermentation (OG)
Take your gravity reading after the boil is cooled and the wort/must is well mixed. This is your Original Gravity — it represents the total fermentable sugars.
4. After Fermentation (FG)
Take your final reading when gravity is stable for 2-3 days. This is your Final Gravity — the remaining unfermented sugars. Lower FG = more complete fermentation.
Common Mistakes
Avoid these pitfalls when measuring ABV
Temperature not corrected
Hydrometers are calibrated to a specific temperature (usually 60°F/15.5°C). Readings at different temperatures will be inaccurate unless corrected.
Refractometer FG without correction
Alcohol changes the refractive index. Using a raw refractometer reading for FG (after fermentation) will give a falsely high gravity. Apply a correction calculator.
Reading too early
Taking FG before fermentation is fully complete leads to a lower calculated ABV. Wait until gravity is stable for 2-3 consecutive days.
CO₂ affecting hydrometer
Dissolved CO₂ in young beer creates bubbles on the hydrometer, making it float higher and giving a falsely low reading. Degas the sample first.
About the ABV Calculator
How this calculator works
This calculator computes Alcohol by Volume (ABV) using industry-standard formulas. In Brewing mode, enter your Original Gravity (OG) and Final Gravity (FG) in SG, Plato, or Brix to get ABV, attenuation, calories, and proof. In Cocktail mode, add ingredients with their volumes and ABV percentages to calculate the final drink strength and standard drink count. The ABV ↔ Proof converter instantly converts between ABV, US Proof, and Alcohol by Weight.
Frequently Asked Questions
Common questions about ABV, gravity, and alcohol calculations
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