ABV Calculator
Enter your hydrometer readings to find ABV, apparent attenuation, and calories.
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Common Beer Styles
| Style | OG Range | FG Range | ABV |
|---|---|---|---|
| Light Lager | 1.028–1.040 | 0.998–1.008 | 2.8–4.2% |
| Pale Ale | 1.045–1.060 | 1.010–1.015 | 4.5–6.2% |
| IPA | 1.056–1.075 | 1.008–1.014 | 5.5–7.5% |
| Stout | 1.036–1.075 | 1.007–1.018 | 4.0–6.5% |
| Belgian Tripel | 1.075–1.085 | 1.008–1.014 | 7.5–9.5% |
| Barleywine | 1.080–1.120 | 1.016–1.030 | 8.0–12.0% |
How to Calculate ABV from Gravity
Alcohol by volume (ABV) is calculated from the difference between original gravity (before fermentation) and final gravity (after fermentation). The yeast converts sugar to alcohol, lowering the gravity.
The simple formula ABV = (OG − FG) × 131.25 works well for most homebrew. For higher gravity beers (above 1.070), use the alternate formula for better accuracy.
Example: starting gravity 1.052 (a medium-strength ale), finishing at 1.010 after fermentation. ABV = (1.052 − 1.010) × 131.25 = 5.5%. For stronger beers above OG 1.080, use the more accurate formula: ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794).
Gravity is measured with a hydrometer or refractometer. Hydrometers give direct gravity readings at calibration temperature (usually 60°F/15°C); correct for temperature if measuring a hot sample. Refractometers require a post-fermentation correction factor because alcohol changes the refractive index.
Final gravity indicates fermentation completeness. A stable reading on two consecutive days (24–48 hours apart) confirms fermentation has stopped. Bottling before FG stabilizes can cause over-carbonation or bottle explosions.
Most homebrew yeasts attenuate 70–80% of fermentable sugars. Apparent attenuation = (OG − FG) / (OG − 1.000) × 100%. A 75% attenuation from OG 1.060 gives FG ≈ 1.015.
See also: IBU Calculator · Mash Water Calculator