Estimate alcohol by volume from a beer's original gravity and final gravity readings.
| ABV (%) | – |
Use this ABV calculator after fermentation when a hydrometer (or a converted refractometer reading) has given you original gravity (OG) and final gravity (FG) and you want a homebrew alcohol-by-volume estimate.
The calculation is ABV (%) = (original gravity − final gravity) × 131.25. Original gravity must be higher than final gravity. This is the simple homebrew formula used on many brewing sites; it is not the full TTB or laboratory alcohol table. For watering down a distilled spirit, use the alcohol dilution calculator instead.
Original gravity: Specific gravity of the wort before fermentation. Enter 1.05 for a typical ale wort (a hydrometer reading of 1.050).
Final gravity: Specific gravity after fermentation. 1.01 is a common fairly dry finish. It must be lower than OG.
ABV (%): Estimated alcohol by volume of the finished beer.
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