What gravity scale should I use?

Use specific gravity (SG) units on the 1.000 scale, which is what most hydrometers read. A typical beer OG is between 1.035 and 1.070, and FG is between 1.008 and 1.018.

Which formula is more accurate?

The standard formula (OG − FG) × 131.25 is accurate for most beers under 6% ABV. The alternate formula accounts for changes in liquid density during fermentation and is more precise for high-gravity beers, wines, and meads above 6% ABV.

Can I use Plato or Brix readings?

This tool uses specific gravity. To convert Brix to SG, use the approximation SG ≈ 1 + (Brix / 259). For example, 14 Brix ≈ 1.054 SG.

What is apparent attenuation?

Apparent attenuation measures how much of the fermentable sugars were consumed. It is calculated as ((OG − FG) / (OG − 1.000)) × 100. A typical ale yeast achieves 70–80% attenuation.

My FG is higher than my OG — what happened?

This indicates a measurement error. The FG must always be lower than OG because yeast consumes sugars and lowers the gravity. Check that you entered both values correctly and that your hydrometer is calibrated.

ABV Calculator

Name: ABV Calculator
Availability: InStock
Author: Nham Vu

Enter your original gravity and final gravity readings to instantly calculate ABV for your homebrewed beer, wine, or cider.

Gravity Readings

Beverage Type

Original Gravity (OG)

Gravity before fermentation (e.g. 1.055)

Final Gravity (FG)

Gravity after fermentation is complete (e.g. 1.012)

Quick Presets

Results

Enter gravity readings and click Calculate ABV.

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Summary

Enter your original gravity and final gravity readings to instantly calculate ABV for your homebrewed beer, wine, or cider.

How it works

Measure the original gravity (OG) of your wort or must before fermentation begins.
After fermentation is complete, measure the final gravity (FG) with a hydrometer.
Enter both values in the fields below (e.g. OG = 1.055, FG = 1.010).
The standard formula ABV = (OG − FG) × 131.25 is applied immediately.
The alternate formula ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794) is also shown for comparison.
Use the standard result for most beers; the alternate formula is more accurate above 6% ABV.

Use cases

Calculate ABV for a homebrewed ale, lager, or stout.
Determine alcohol content of homemade wine or mead.
Verify fermentation is complete by comparing expected FG to actual FG.
Compare standard vs. alternate ABV formulas for high-gravity batches.
Estimate alcohol content of hard cider or kombucha.
Track fermentation progress across multiple gravity readings.
Label homebrew bottles with an accurate ABV figure.
Troubleshoot a stuck fermentation by checking attenuation.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu