Alcohol Dilution Calculator – Calculate Water to Add for Target ABV

Dilute spirits to your desired strength with our Alcohol Dilution Calculator. Enter starting ABV and volume along with your target ABV to calculate exactly how much water to add — perfect for home distillers and bartenders.

Initial ABV (%)

Target ABV (%)

Initial Volume

Unit

Common Bottling Strengths:

• 40% ABV (80 proof) - Standard
• 43% ABV (86 proof) - Premium
• 46% ABV (92 proof) - Cask strength entry
• 50% ABV (100 proof) - Bottled in bond

Dilution Results

Enter dilution details and click Calculate to see results

Dilution Tips for Spirits

Water quality: Use distilled or spring water. Tap water can add off-flavors.
Temperature: Dilute at room temperature for accurate measurements.
Resting: Let diluted spirits rest 24-48 hours for flavors to integrate.
Step dilution: For large dilutions, add water in stages for better mixing.
Taste testing: Dilute slightly less than calculated, taste, then add more if needed.

Note: Dilution can "open up" spirits, releasing aromas and flavors that are masked at higher ABV. Many whiskies benefit from a few drops of water even after bottling.

How to Use This Alcohol Dilution Calculator

Enter your starting measurements

Input the initial ABV (alcohol by volume) of your spirit and the volume you have. Select your volume unit (ml, liters, fl oz, or gallons).

Set your target ABV

Enter the ABV percentage you want to reach. Common bottling strengths are 40% for standard spirits, 43-46% for premium expressions, and 50% for bottled-in-bond.

Calculate and follow the results

Click Calculate to see exactly how much water to add. The calculator also shows your final volume, proof before and after, and provides recommendations based on your target strength.

Understanding Alcohol Dilution

What Is Dilution?

Dilution means reducing the alcohol concentration (ABV) of a spirit by adding water. When you add water to high-proof alcohol, the total volume increases while the amount of pure alcohol stays the same, resulting in a lower percentage of alcohol by volume.

The Dilution Formula

Alcohol dilution follows the basic concentration formula:

C₁V₁ = C₂V₂

Where C₁ is the initial concentration (ABV), V₁ is the initial volume, C₂ is the target concentration, and V₂ is the final volume. To find how much water to add, calculate V₂ and subtract V₁.

Why Dilute Alcohol?

Taste: High ABV can overwhelm your palate. Dilution opens up flavors and aromas that are masked at higher strengths.
Safety: Drinking spirits at very high ABV (above 60%) can be harsh and potentially harmful.
Regulations: Most countries require bottled spirits to be between 37.5% and 50% ABV for legal sale.
Consistency: Dilution allows producers to maintain consistent ABV across batches.

Proof vs ABV

In the United States, proof is simply twice the ABV percentage. So 40% ABV equals 80 proof, 50% ABV equals 100 proof, and so on. The term comes from historical methods of testing alcohol content. In the UK, proof was historically calculated differently (about 1.75 times ABV), but they now use ABV exclusively.

Common Alcohol Dilution Scenarios

Scenario	Starting ABV	Target ABV	Purpose
Moonshine	80%	40%	Typical drinking strength
Home Distilling	95%	40-50%	Standard bottling strength
Tinctures	95%	60-70%	Optimal extraction strength
Cocktails	40%	10-15%	After mixing with other ingredients

Dilution Water Calculation Examples

Example 1: Diluting Moonshine

Starting: 1 liter at 80% ABV
Target: 40% ABV
Calculation: (1L × 80%) ÷ 40% = 2L final volume
Water to add: 2L - 1L = 1 liter of water

Example 2: Home Distilling

Starting: 500ml at 95% ABV
Target: 50% ABV
Calculation: (500ml × 95%) ÷ 50% = 950ml final volume
Water to add: 950ml - 500ml = 450ml of water

Example 3: Adjusting Whiskey

Starting: 750ml at 60% ABV
Target: 40% ABV
Calculation: (750ml × 60%) ÷ 40% = 1125ml final volume
Water to add: 1125ml - 750ml = 375ml of water

Important Dilution Tips

Use distilled or reverse osmosis water

Tap water contains minerals and chlorine that can affect flavor. Distilled or RO water is neutral and won't introduce off-flavors to your spirit.

Add alcohol to water, not water to alcohol

This is a safety and mixing best practice. Adding alcohol to water helps prevent localized high-concentration zones and promotes better mixing.

Let diluted spirits rest before bottling

After dilution, give your spirit 24-48 hours to rest. This allows the water and alcohol to fully integrate and flavors to stabilize.

Temperature affects final volume

Alcohol and water expand and contract at different rates with temperature changes. For precise measurements, dilute at room temperature (around 20°C / 68°F).

Watch for louche (cloudiness)

Some spirits, especially those with botanical oils like absinthe or gin, may turn cloudy when diluted. This is normal and called the louche effect.

Frequently Asked Questions

How do I calculate how much water to add?

Use the formula: Water to add = (Initial Volume × Initial ABV ÷ Target ABV) - Initial Volume. For example, to dilute 1 liter of 60% ABV to 40%: (1000ml × 60 ÷ 40) - 1000ml = 500ml of water. Or simply use this calculator to do the math for you.

What kind of water should I use for dilution?

Distilled water or reverse osmosis (RO) water is best. These have no minerals, chlorine, or other compounds that could affect the taste of your spirit. Avoid tap water and most bottled spring waters, as their mineral content can introduce off-flavors or cause cloudiness.

Can I dilute any type of alcohol?

Yes, you can dilute any distilled spirit - whiskey, vodka, rum, gin, moonshine, neutral spirits, and more. However, some aged spirits may benefit from gradual dilution and resting to allow flavors to re-integrate. Flavored spirits and liqueurs may behave differently due to added sugars and flavorings.

Does diluting alcohol reduce the total alcohol content?

No. Dilution reduces the concentration (percentage) of alcohol, but the total amount of pure alcohol stays the same. If you dilute 1 liter of 50% ABV spirit to 40% ABV, you still have 500ml of pure alcohol - it's just spread across a larger total volume (1.25 liters instead of 1 liter).

Why does my diluted spirit look cloudy?

Cloudiness after dilution is called "louche" or "ouzo effect." It happens when certain compounds (like essential oils from botanicals or fatty acids from grains) that are soluble in high-proof alcohol become insoluble at lower ABV. It's harmless and common with gin, absinthe, ouzo, and some whiskies. Filtering through a coffee filter can remove cloudiness if desired.

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