Example Data Table
| Scenario | Original Gravity | Final Gravity | Batch Volume (L) | Estimated ABV |
|---|---|---|---|---|
| Pale Ale Batch | 1.050 | 1.010 | 20 | 5.25% |
| Stout Batch | 1.065 | 1.018 | 18 | 6.17% |
| High Gravity Brew | 1.080 | 1.012 | 23 | 8.93% |
Formula Used
Gravity method: ABV = (OG − FG) × 131.25. This common brewing estimate converts specific gravity drop into alcohol by volume.
ABW estimate: ABW ≈ ABV × ethanol density. It compares alcohol mass to total beverage mass using a practical density approximation.
Pure ethanol volume: Ethanol volume = beverage volume × ABV ÷ 100. Ethanol mass = ethanol volume × density.
Proof conversion: US proof = ABV × 2. UK proof = ABV × 1.75.
How to Use This Calculator
- Select either the gravity method or sample ethanol method.
- Choose the proof system you want to compare.
- Enter ethanol density, or keep the default 0.789 g/mL.
- For brewing estimates, enter original gravity, final gravity, batch volume, and temperature.
- For direct sample checks, enter sample volume and known ABV.
- Press the calculate button to display the result above the form.
- Use the CSV or PDF buttons to export the current result set.
Frequently Asked Questions
1. What does ABV mean?
ABV means alcohol by volume. It shows the percentage of pure ethanol in the total beverage volume.
2. Why use original and final gravity?
Gravity drops as sugars ferment into alcohol and carbon dioxide. That change gives a practical estimate of alcohol strength.
3. Is the gravity formula exact?
No. It is a well-known approximation for brewing. Lab methods like distillation or densitometry provide more exact results.
4. What is ABW?
ABW means alcohol by weight. It measures alcohol mass relative to total beverage mass and is lower than ABV for the same drink.
5. Why is temperature included?
Hydrometer readings shift slightly with temperature. The calculator shows a simple adjustment around the standard 20°C reference point.
6. Can I export my results?
Yes. Use the CSV or PDF buttons after entering values. The file will contain the main alcohol metrics and summary notes.
7. Which density value should I use?
Pure ethanol near room temperature is commonly approximated as 0.789 g/mL. Change it only if your method requires another reference.