I’ve been seeing a lot of DIY hand sanitizer recipes lately, thanks to the novel coronavirus (covid-19). Unfortunately, a lot of the DIY recipes leave you with a product that is less than the CDC recommended 60% alcohol. I want to share why and how that happens, and give you a basic recipe to make your own hand sanitizer that follows the CDC guidelines.

First, it’s important to understand what your bottle of rubbing alcohol is: a bottle of 100% isopropyl alcohol and water. “Wait, my bottle says 70% rubbing alcohol!” I assure you, it’s still 100% alcohol mixed with water. Imagine an empty bottle, now put pure (100%) alcohol into the bottle, but only fill it halfway. Now fill the bottle the rest of the way with distilled water. You now have 50% rubbing alcohol because the solution (two or more things mixed together is a solution) is made up of 50% isopropyl alcohol and 50% water.