Alcohol Dilution Calculator — Blend ABV & Convert Proof
Dilute alcohol with water, blend two strengths, plan a target batch, or convert ABV and U.S. proof with formulas, tables, and a visual mixture breakdown.
How much water should I add?
Reduce a beverage from its current alcohol by volume to a lower target strength while preserving the estimated amount of pure alcohol.
How much of a second liquid should I add?
Start with a known amount of liquid A, then solve the amount of liquid B needed to land between their two strengths.
Split a target batch between two strengths
Enter the finished quantity and target ABV. The calculator divides it between a stronger component and a weaker component.
Convert ABV and U.S. proof
Convert either direction and, when a volume is entered, estimate pure alcohol volume and U.S. proof gallons.
Mixture proportions
Calculation
Mixture details
Alcohol dilution calculator formula
Dilution uses the balance V1 × A1 = V2 × A2. The estimated pure-alcohol amount stays constant while water increases total volume and lowers ABV.
Blend two alcohol strengths
For two liquids, the calculator balances pure alcohol from both components. The requested target must sit strictly between their ABV values.
Plan a target batch
Choose a finished volume and target strength, then split the batch between stronger and weaker components. This is useful for repeatable recipe planning and scale-up.
ABV to U.S. proof converter
U.S. proof is twice alcohol by volume, so 40% ABV equals 80 proof. Other countries and historical systems may define proof differently.
Frequently asked questions
How much water do I add to reduce ABV?
Multiply starting volume by current ABV, divide by target ABV, then subtract the starting volume. Keep all volumes in the same unit.
Can I blend two beverages to an exact ABV?
This calculator gives a volume-balance estimate. Sugar, dissolved solids, temperature, and alcohol-water contraction can make a measured final value differ.
Why must the target be between the two strengths?
Mixing only two components cannot produce an ABV above both or below both. Add a different-strength component or change the target.
Is 40% ABV always 80 proof?
It is 80 proof in the U.S. system. The TTB defines proof for distilled spirits as twice percent alcohol by volume.
Does this replace a hydrometer or laboratory measurement?
No. It is a planning estimate based on stated ABV and additive volume. Regulatory proofing uses temperature correction, density data, and approved measurement procedures.
Method and measurement limits
The calculator treats entered ABV as volume percent and assumes component volumes add directly. Real ethanol-water mixtures can contract, and readings depend on temperature and dissolved material. For official proofing, see the TTB proofing tutorial, the TTB proof FAQ, and the NIST alcohol density and temperature tables.
Scope and safety
This tool is for beverage recipe planning. It does not determine drinking safety, legal compliance, distillation safety, sanitizer formulation, medical dosing, or laboratory concentration. Verify finished products with suitable measurement and follow applicable law and professional guidance.
