What this calculator does
DIY hand sanitizer recipe (WHO formula) works out scales the WHO alcohol-based handrub formulations to any batch size. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaIngredients scaled from the WHO 10-litre reference recipe: alcohol, 3% hydrogen peroxide, 98% glycerol, topped up with water
The inputs explained
| Field | What to enter |
|---|---|
| Batch size (mL) | A number, measured in mL. Starts at 500. |
| Alcohol type | Choose from Ethanol 96%, Isopropyl alcohol 99.8%. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with batch size
Every other input is held at the calculator’s starting values while batch size varies. Select any row to load that scenario into the calculator.