What is the difference in the percentages of Isopropyl Alcohol?

Author: Sydney Solvents   Date Posted:14 March 2018 

Have you noticed that there is a whole range of percentages of Isopropyl Alcohol, like 70%, 50%, 100%, 99%? It can be confusing to choose between them, and so we are here to help...


Sydney Solvents sell the best range of Isopropyl Alcohol from 70%, 99% to 100%. It is important to understand that a lot of sellers on the market will dilute their product down with unrefined products, causing impurities within the Isopropyl Alcohol, whereas Sydney Solvents is consistently of high quality.

When looking at the difference between the percentages the main is the difference of the moisture content and the strength of the Isopropyl Alcohol. The importance of this is when it comes to the application, which we will get to. Higher moisture means that is slows down the evaporation, whereas the highest percentage of 100% evaporates off very quickly leaving little to no residue.

Here we break down each of the percentages

Isopropyl Alcohol 100 - Isopropyl Alcohol 100%

Key features:

  • Higher strength
  • Will evaporate off the surface quickly
  • Useful for cleaning applications

The higher percentages of Isopropyl Alcohol are used for cleaning purposes like disinfecting, window cleaning, stainless steel cleaner and when you need to kill bacteria, as well as many other uses. The higher the percentage like Isopropyl Alcohol 100% the greater the evaporation rate, and it is great as it dries faster. The high grades of Isopropyl Alcohol 100% are suitable for the majority uses and is commonly used by industrial users and cleaners.

Isopropyl Alcohol 99%

Key features:

  • Higher strength
  • Perfect for 99% Isopropyl formulations
  • Great for cleaning

What’s the difference between 99% and 100%? We get asked this question a lot. The difference is the 1% of moisture content and the importance of this is when it comes to formulations some require the 99% strength, and that’s when you should decide to use it over the 100%. It has similar features to the 100% in the fact that it does clean and disinfect, evaporating off quickly.

Below Isopropyl Alcohol 70%

Key features:

  • Higher moisture content
  • Stays on surface longer, so it has time to kill bacteria
  • Used as a rubbing alcohol for skin

A common percentage is Isopropyl Alcohol 70%, which is the grade recommended for rubbing alcohol when applying it to the skin. The lower grade of Isopropyl Alcohol 70% means that it is not as harsh to the skin, but it is still effective. Also, the lower grade is great for getting rid of the bugs off the plants and also disinfecting as the water content mixed with the alcohol fights against growing viruses and fungus.

The reason you would choose 70% over 100% when it comes to killing mealy bugs is because the higher moisture content in the rubbing alcohol means that it will stay on the bugs for longer, allowing it to work and kill the bugs. 

So which one should you get?

No matter what the percentage, Isopropyl Alcohol 100%Isopropyl Alcohol 99% or Isopropyl Alcohol 70% are beneficial product to have in the workshop and household. The many uses it has makes it a handy product to have around. If you’re cleaning like electronics or disinfecting medical equipment get either the 100% or 99% and if you’re using it on the skin or spraying plants use 70% Isopropyl Alcohol. Depending on your application will impact of the percentage. If you need help feel free to give us a call on 02 4722 5060, and we will be happy to help out.

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