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Alcohol Dilution Calculator

Table of contents

How to use the alcohol dilution calculatorHow to dilute alcohol?Sweetness of the homemade alcoholAlcohol contractionFAQs

Our alcohol dilution calculator allows you to efficiently compute amount of alcohol and water needed for any homemade alcohol solutions. It doesn't matter if you're trying to convert 91 isopropyl alcohol to a 70% solution or distilling your own fruity liquor – this tool will be helpful in all possible scenarios.

Check the Show contraction volume box for the alcohol contraction🍾

Remember that our calculators work in all directions – we'll help you with whatever you're trying to calculate!

The article below will explain the theory of alcohol dilution, present the alcohol dilution reduction table, and provide the rules of managing alcohol sweetness.

How to use the alcohol dilution calculator

There are many ways to use the alcohol percentage calculator for spirits - we'll show you the most popular way.

  1. You need to choose what kind of strong alcohol are you going to use?

    • Strongest consumable alcohol, rectified spirit, has an alcohol content of 95% – it is often used for making tinctures.

    • Standard vodka has an alcohol content of 40%.

  2. Are you going to mix it with water or with a weaker spirit? 🚰

    • Enter 0% for water.

    • Remember, it has to have a lower percentage than the strong alcohol!

  3. Choose your target alcohol content.

    • It also has to be lower than the strong alcohol percentage.
  1. Enter the amount of strong alcohol you want to use.

  2. Your results are here! – you'll get the amount of water/weak alcohol you need to obtain your target alcohol concentration.

If you check the Show contraction volume box, you'll also get the amount of alcohol lost due to contraction.

Did you enjoy using this alcohol dilution calculator? Then you might like to try our other alcohol-related tools:

How to dilute alcohol?

Sometimes you may need to work out an alcohol dilution, but heaven forbid you can't get a hold of this distilling calculator! We know that will never happen, but if you want to calculate alcohol dilution with your own knowledge – follow the guide below!

  1. The easiest way to calculate all the data needed is to use the cross method.
Cross method for alcohol dilution calculator.


  • A – Concentration of alcohol in the stronger spirit, given as a %;
  • B – Concentration of the weaker spirit or water, given as a %;
  • C – Target concentration of our final solution;
  • D = C - B is the parts of strong alcohol that we need to add; and
  • E = A - C is the parts of weaker spirit/water that we need to add.
  1. Enter all your data into the cross scheme and calculate D and E. (It's easy to remember – you always have to subtract the lower value on the cross from the upper value.)

  2. The result is a ratio of the strong alcohol needed and the weaker spirit/water needed.

    Let's say that D = 65 and E = 30, and we have 100 ml of strong alcohol. That means that for every 65 parts of stronger alcohol, we'll need to add 30 parts of weaker alcohol/water.

    We need to use the proportions:

    D --- Amount of strong alcohol

    E --- Amount of water needed

    Let's transform it:

    Amount of water needed = (E × Amount of strong alcohol)/ D

    Amount of water needed = (30 × 100 ml)/ 65

    Amount of water needed = 46.15 ml

  3. That's that - we got it!

But how to dilute 91 isopropyl alcohol to 70%?

Simply use the 91% isopropyl alcohol as the stronger spirit and use water as a weaker spirit. Your target value is 70%.

Want to learn more? You may also try our tool for general solution dilution. ⚗️

Sweetness of the homemade alcohol

Our dilution calculator in percent won't tell you how sweet your alcohol should be - that decision is all yours. However, we decided to gather all the information to make it as easy as possible.

What can we use to sweeten up our alcohol?

  • We can use either syrup, honey, or regular sugar of any kind. Honey is 30% less sweet than sugar.

What is the volume of added sugar?

  • 100 g of sugar takes 60 ml of volume
  • 100 g of honey takes 75 ml of volume

What are the ranges of sweetness for alcohol?

The presented ranges are characteristic of tinctures

  • Dry, up to 50 g of sugar in 1 L of solution;
  • Semidry, 51-120 g in 1 L of solution;
  • Semisweet, 121-220 g in 1 L of solution;
  • Sweet, 221-330 g in 1 L of solution; and
  • Liqueur and crème, >331 g in 1 L of solution.

Alcohol contraction

Bad news - when you mix alcohol solutions, their volume shrinks. This is due to some of the alcohol molecules present being able to fit neatly between the water molecules. This process is called alcohol contraction. Luckily, the amount of contraction is not that large.

How much spirit are we going to lose while mixing our alcohol?

Find the estimated amount in the table below:

Total amount of mixture

Alcohol concentration (in %)

Amount lost (in mL)

1 liter



1 liter



1 liter



1 liter



1 liter



1 liter



1 liter



1 liter



1 liter



1 liter




How do you calculate alcohol dilution?

To calculate how much of a weaker spirit or water you need to add to dilute your alcohol:

  1. Multiply the concentration of the weaker spirit in % (0% for water) by the volume of the stronger spirit.
  2. Divide the result by the concentration of the stronger spirit (also in %).
  3. Subtract this result from the volume of the stronger spirit.

Can I dilute 91% isopropanol alcohol to 70%?

Yes! You'll need 900 mL of water to dilute 91% isopropanol down to 70%. To calculate it, follow these steps:

  1. Measure the volume of strong alcohol (isopropanol) you have. Let's assume it is 3 liters.
  2. Subtract the lower concentration from the stronger concentration:
    91% − 70% = 21%
  3. Multiply the result by the volume:
    21% × 3 L = 0.63 L
  4. Finally, divide this result by the lower concentration:
    0.63 L / 70% = 0.9 L = 900 mL

How do you dilute 80% alcohol?

To dilute 80% alcohol, first define the volume of the stronger spirit and the alcohol concentration of the weaker spirit (and remember that water is 0% alcohol). Then you can:

  1. Subtract the lower concentration from the stronger concentration.
  2. Multiply this result by the volume of the stronger spirit.
  3. Divide the result by the desired concentration.

For example, if you want to dilute 1 liter of 80% alcohol down to 30% using water, calculate the volume of water needed as follows:

(80% − 30%) × 1 L / 30% = 1.6667 L

Can you dilute alcohol with water?

Yes, you can dilute alcohol with water! Simply set the percentage of the weaker alcohol in the formula for alcohol dilution to 0. You can also dilute alcohol in your body system by drinking water. Once the liver metabolizes it, the alcohol concentration will slowly reduce.

Does sugar increase the volume of alcohol?

Yes, sugar increases the volume of alcohol. Typically, syrup, honey or regular sugar of any kind is used as a sweetener, where honey is 30% less sweet than sugar. As a rule of thumb, you can say that:

  • 100 g of sugar takes 60 ml of volume; and
  • 100 g of honey takes 75 ml of volume.

Alcohol content

Alcohol volume

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