Alcohol Dilution Calculator

Alcohol Dilution Calculator Guide

An alcohol dilution calculator computes how much water (or stronger spirit) to add so a mixture reaches a target alcohol by volume (ABV). This page explains mass‑balance formulas, Pearson’s square, and common pitfalls (temperature, measurement error) so you can hit your target more precisely.

What is Alcohol Dilution Calculator?

The alcohol dilution calculator helps distillers, bartenders, and hobbyists reduce or increase ABV for spirits, liqueurs, and infusions. It supports straight dilution, fortification (adding higher‑proof spirit), and blends.

How to Use the Alcohol Dilution Calculator

1. Choose the task: dilution (add water), fortification (add spirit), or two‑spirit blend.
2. Enter inputs: starting volume V₁ and ABV C₁ (%), additive ABV C₂ (%), and target ABV Cₜ (%).
3. Compute the required additive volume V₂ and final volume Vₜ.
4. Adjust for temperature if needed (best results near 20 °C / 68 °F).
5. Record and label the batch—include date, inputs, and target ABV.

Formulas & Methods

• Mass balance (two‑component)

  V₁·C₁ + V₂·C₂ = Vₜ·Cₜ
  Vₜ = V₁ + V₂   (approximate; volumes aren’t perfectly additive)
  

  Solve for V₂ given V₁, C₁, C₂, Cₜ. Use ABV as a fraction (e.g., 40% → 0.40).
• Pearson’s square (fast rule‑of‑thumb)
  Write C₁ and C₂ at left corners of a square, the target Cₜ in the center. Subtract diagonally to get parts of each component. Ratio of parts gives the mixing ratio; scale to the volume you need.
• Assumptions & limitations
  • Small error from non‑additive volumes and temperature.
  • ABV refers to volume percent at reference temperature.
  • Use calibrated glassware or a scale for better accuracy.

Examples

Example A — Diluting neutral spirit
Target: 40% ABV vodka from 1.0 L at 95% ABV.
Mass balance:

V₁·C₁ + V₂·C₂ = (V₁+V₂)·Cₜ
1.0·0.95 + V₂·0.00 = (1.0 + V₂)·0.40
0.95 = 0.40 + 0.40·V₂  ⇒  V₂ = 1.375 L (water)
Vₜ ≈ 2.375 L at 40% ABV

(Real mixtures may differ slightly; measure final ABV if critical.)

Example B — Fortifying wine
Raise 0.75 L of 12% ABV wine to 18% using 95% ABV spirit.

0.75·0.12 + V₂·0.95 = (0.75+V₂)·0.18
0.09 + 0.95·V₂ = 0.135 + 0.18·V₂
0.77·V₂ = 0.045  ⇒  V₂ ≈ 0.0584 L (≈ 58 mL of spirit)
Vₜ ≈ 0.808 L at 18% ABV

| Scenario | Inputs | Add | Final | |---|---|---:|---:| | Dilute 95% → 40% | 1.0 L @95% | 1.375 L water | 2.375 L @40% | | Fortify 12% → 18% | 0.75 L @12% + 95% spirit | 0.058 L spirit | 0.808 L @18% |

Pro Tips & Best Practices

• Use ABV as a fraction in formulas (e.g., 37.5% → 0.375) to avoid mistakes.
• Chill components to similar temperatures before mixing; read hydrometer specs for temperature correction.
• Mix, rest, then measure—ABV readings stabilize after thorough mixing and degassing.
• Label clearly: date, volumes, ABVs, calculation method.
• For sweet liqueurs, account for sugar’s volume; measure final ABV if exact labeling matters.

Related Calculators

• Coffee Ratio Calculator
• Recipe Converter

FAQ

Q: What is an alcohol dilution calculator?

A: A tool that tells you how much water (or higher‑proof spirit) to add to a known volume at a known ABV to reach a target ABV.

Q: What formula does it use?

A: Mass balance: V1×C1 + V2×C2 = Vt×Ct, where C is ABV (as a fraction) and V is volume.

Q: What is Pearson’s square?

A: A quick visual method for two‑component mixing (e.g., spirit and water) to hit a target ABV without algebra.

Q: Does temperature matter?

A: Yes. Alcohol–water volumes are not perfectly additive and are temperature‑dependent. The tool assumes near‑room temperatures and small error.

Q: Is this legal or safe advice?

A: No. This page is informational only. Follow local laws and safety guidance when handling alcohol.

Compliance note: This article is for information only. Follow local laws and safety guidance when handling alcohol.

Call to Action

Use the calculator above to plan dilutions or fortifications. Save your scenarios for repeat batches and consistent results.