# ABV Calculator (Alcohol by Volume)

URL: https://speedycalculator.com/calculators/food/abv/
Last updated: 2026-10-25

> The ABV calculator estimates the alcohol content of home-brewed beer, wine or cider from the original and final gravity readings taken with a hydrometer.

## Inputs

- Original gravity (OG)
- Final gravity (FG)

## Results

- Alcohol by volume
- Apparent attenuation

## Formula

```
ABV ≈ (OG − FG) × 131.25
```

## Explanation

As yeast converts sugar into alcohol, the liquid becomes less dense; the drop in specific gravity reveals the alcohol produced.

### How to use the ABV Calculator

- **Original gravity (OG)**
- **Final gravity (FG)**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Subtract final gravity from original gravity and multiply by 131.25.

### Inputs explained

FieldWhat to enterOriginal gravity (OG)A numberFinal gravity (FG)A number

### What each result means

- **Alcohol by volume** = ([Original gravity (OG)] - [Final gravity (FG)])×131.25
- **Apparent attenuation** = ([Original gravity (OG)] - [Final gravity (FG)])÷([Original gravity (OG)] - 1)×100

## Worked example

Inputs — Original gravity (OG): 1.05; Final gravity (FG): 1.01.

Results — **Alcohol by volume = 5.25 %**; Apparent attenuation = 80 %.

## FAQ

**Is the formula exact?**
It is accurate for typical beers; high-gravity brews need a more advanced formula.

**Do I need to correct for temperature?**
Yes, hydrometers are calibrated for a specific temperature, often 20 °C.

**What formula does the ABV Calculator use?**
ABV ≈ (OG − FG) × 131.25.