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Free ABV calculator for homebrewers and winemakers. Enter original gravity (OG) and final gravity (FG) to get alcohol by volume %, alcohol by weight, calories per 100 ml, US standard drinks per 12 fl oz, and apparent attenuation. Answers “how do I calculate ABV from hydrometer readings?” with worked examples.
Last updated: May 24, 2026
Need drink units for any pour size? Alcohol unit calculator
Alcohol by Volume
5.25%
Alcohol by Weight
4.21%
Calories per 100 ml
29
US std. drinks (12 fl oz)
1.05
Apparent attenuation
80%
Recommendation
Standard craft range — pale ale, IPA, porter, most red wines.
Built for hydrometer-based brewing — not a substitute for lab certification or label compliance testing.
Default OG 1.050, FG 1.010 → 5.25% ABV — typical American pale ale territory.
5.25% ABV ≈ 4.21% ABW using ethanol density 0.79336.
~1.05 US standard drinks (14 g ethanol each) per 12 fl oz bottle at 5.25% ABV.
Default: OG 1.050 · FG 1.010 → 5.25% ABV, 4.21% ABW, 29 kcal/100 ml (alcohol only), 1.05 std. drinks per 12 fl oz, 80% attenuation.
ABV
5.25%
ABW
4.21%
kcal / 100 ml
29
Std. drinks / 12 oz
1.05
Attenuation
80%
| Style | OG range | FG range | ABV | Example |
|---|---|---|---|---|
| American light lager | 1.028–1.040 | 1.000–1.008 | 3.2–4.2% | OG 1.040, FG 1.008 → 4.2% ABV |
| American pale ale | 1.045–1.060 | 1.010–1.015 | 4.5–6.2% | OG 1.050, FG 1.010 → 5.25% ABV (default) |
| IPA / hazy IPA | 1.056–1.075 | 1.010–1.018 | 5.5–7.5% | OG 1.065, FG 1.012 → 6.96% ABV |
| Imperial stout | 1.075–1.115 | 1.018–1.030 | 8–12%+ | OG 1.090, FG 1.020 → 9.19% ABV |
| Belgian tripel | 1.070–1.095 | 1.005–1.016 | 7.5–9.5% | OG 1.080, FG 1.010 → 9.19% ABV |
| Table wine (fermented) | 1.070–1.095 | 0.990–1.000 | 9–14% | OG 1.090, FG 0.995 → 12.48% ABV |
| Method | Formula | When to use |
|---|---|---|
| Papazian / homebrew (this tool) | (OG − FG) × 131.25 | Most common homebrew shortcut; accurate within ~±0.3% ABV for beer gravities |
| ASBC / precise | 131.25 × (OG − FG) / (1.05 × (FG / OG)) | Better for high-gravity beer and wine; accounts for dissolved CO₂ and extract |
| Refractometer (finished beer) | Use correction after fermentation | OG from Brix + FG Brix with yeast correction tables — not raw Brix difference |
| Attenuation | Yeast examples | Notes |
|---|---|---|
| 65–72% | English ale, some lagers | Malt-forward, sweeter finish |
| 72–78% | American ale, Kölsch | Balanced — default OG 1.050 / FG 1.010 is 80% apparent attenuation |
| 78–85% | Saison, Belgian, some hybrids | Dry, crisp finish |
| 85%+ | Super high attenuation strains | Very dry; verify FG stability |
Fermentation converts sugars into ethanol and CO₂. The gravity drop (OG − FG) correlates with how much alcohol is in the finished beer or wine. Homebrewers use specific gravity because it is easy to measure with inexpensive equipment; the 131.25 factor bundles unit conversions into one number Papazian popularized in homebrew literature.
ABV = (1.050 − 1.010) × 131.25 = 5.25%ABW ≈ 4.21% (from ABV via ethanol density)Attenuation = (0.040 ÷ 0.050) × 100 = 80%Std. drinks (12 fl oz) = (355 × 0.0525 × 0.789) ÷ 14 ≈ 1.05Have ABV% and serving size? Convert to alcohol units (US / UK / AU) or standard drinks by beverage type.
OG 1.040 · FG 1.008
4.2% ABV · 0.84 std. drinks / 12 oz
OG 1.080 · FG 1.020
7.88% ABV · 75% attenuation
OG 1.090 · FG 0.995
12.47% ABV · verify FG with wine hydrometer
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