Enter your current alcohol percentage, current volume, and target alcohol percentage to find out exactly how much water to add. The Alcohol Dilution Calculator shows you the water needed, the final volume, and a breakdown of alcohol vs. water — perfect for home distillers and moonshine makers.
Water to Add
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Final Volume
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Pure Alcohol in Blend
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Final Alcohol Content
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The calculator uses the formula: Final Volume = (Current Volume × Current ABV) ÷ Target ABV. The water to add is simply Final Volume minus Current Volume. This assumes the volume of pure alcohol remains constant during dilution. Note that contraction (a slight volume reduction when mixing alcohol and water) is not accounted for.
Freshly distilled spirits typically come off the still at a very high alcohol content — sometimes 70–90% ABV. Most spirits are bottled between 37.5% and 50% ABV. Diluting with water brings the spirit to a drinkable and legally compliant strength, and can also improve the flavor profile.
Always use pure, filtered, or distilled water. Tap water can introduce chlorine, minerals, or off-flavors that affect the taste of your spirit. Many home distillers use reverse osmosis (RO) water or bottled spring water for best results.
Contraction refers to the slight reduction in total volume that occurs when you mix alcohol and water — the final volume is slightly less than the sum of both liquids. For most home distilling purposes this effect is small (typically 1–3%), so this calculator omits it to keep things simple. Professional distilleries use specialized tables (like OIML or TTB tables) to account for it precisely.
%vol stands for percent by volume, commonly known as ABV (Alcohol By Volume). It indicates how many milliliters of pure ethanol are present in 100 mL of the total liquid. For example, a 40%vol spirit contains 40 mL of pure alcohol per 100 mL of liquid.
Yes. The dilution calculation is universal and works for any ethanol-based spirit regardless of what it is made from. Whether you are cutting moonshine, proofing whiskey, or blending vodka, the same formula applies.
You cannot increase alcohol content simply by adding water — dilution only lowers ABV. If you enter a target ABV higher than your current ABV, the calculator will indicate that the dilution is not possible. To increase ABV you would need to redistill or blend with a higher-strength spirit.
This calculator is accurate for practical home distilling purposes using the standard dilution formula. For very precise commercial or laboratory applications, you should additionally account for contraction using official alcohol measurement tables (OIML or TTB). Always measure your actual ABV with a calibrated alcohol hydrometer or refractometer after diluting.