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Alcohol Dilution Calculator

Enter your values below to get the result first, then scroll for the full explanation and guidance.

Step 1 • Add values

Use the calculator

Enter your values below to generate an instant result. You can update the inputs at any time to compare different scenarios.

Example: to make 1,000 ml at 20% ABV from a 40% ABV drink, use 500 ml of the drink and add 500 ml of diluent.

Results refresh instantly as values change.

Starting drink volume

500 mlAdd 500 ml of alcohol-free diluent

Starting drink volume: 500 ml (Add 500 ml of alcohol-free diluent)

This ideal dilution estimate conserves pure-alcohol volume using C1V1 = C2V2. It assumes additive volumes and no alcohol loss.

Dilution summary

This ideal dilution estimate conserves pure-alcohol volume using C1V1 = C2V2. It assumes additive volumes and no alcohol loss.

Result snapshot

A quick visual read of the values behind this result.

Starting ABV40%
Target ABV20%
Modelled pure alcohol200 ml

Recommended next checks

  • →Measure both volumes accurately and verify the final strength when precision matters.
  • →Do not use this estimate as production, duty, licensing, consumption, or drinking-safety advice.
Starting ABV
40%
Target ABV
20%
Modelled pure alcohol
200 ml

Try different values to compare results.

Enter the starting ABV, lower target ABV and desired final volume. The calculator preserves the modelled pure-alcohol volume and estimates how much starting drink and alcohol-free diluent are needed.

Fast to use

Built for comparison

Clear result output

Table of Contents

5

About Alcohol Dilution Calculator

Alcohol Dilution Calculator helps you work through the main numbers for this topic quickly with a simple input flow and an instant result.

Use the calculator result as a practical starting point, then review the explanation and assumptions on the page if you want more context.

Alcohol dilution formula

The calculation uses C1V1 = C2V2. Starting drink volume equals target ABV multiplied by final volume, divided by starting ABV. Added diluent is final volume minus starting drink volume.

HMRC expresses alcohol content by multiplying product volume by ABV to obtain pure-alcohol volume. This calculator applies the same conservation principle to a simplified dilution model.

Formula explained

Calculation flow

This calculator is structured for fast UK-focused estimates with clear inputs, repeatable logic, and instant results.

Formula

Input values -> calculation engine -> instant result

How the result is built

1Enter the values requested in the form.
2The calculator applies the configured formula logic.
3The result updates instantly with a breakdown.
4Use the output to compare scenarios quickly.

Example

Example: to make 1,000 ml at 20% ABV from a 40% ABV drink, use 500 ml of the drink and add 500 ml of diluent.

Assumptions

  • Conservation model: starting ABV x starting volume = target ABV x final volume.
  • The target ABV must be lower than the starting ABV. Volumes are treated as additive and no alcohol is lost through evaporation, reaction or measurement error.
  • This is a mathematical dilution estimate, not production, duty, licensing, consumption or drinking-safety advice.

Source basis

  • UK-focused calculator flow
  • Structured input validation
  • Instant result breakdowns

Trust and notes

Assumptions and important notes

This calculator is designed to give a fast estimate using the method shown on the page. Results are most useful when your inputs are accurate and the tool matches your situation.

Use the result as guidance rather than a final diagnosis or professional decision. If the result could affect health, legal, financial, or compliance decisions, verify it with a qualified source where appropriate.

  • Conservation model: starting ABV x starting volume = target ABV x final volume.
  • The target ABV must be lower than the starting ABV. Volumes are treated as additive and no alcohol is lost through evaporation, reaction or measurement error.
  • This is a mathematical dilution estimate, not production, duty, licensing, consumption or drinking-safety advice.

Method

UK calculator guidance

Last reviewed

April 17, 2026