What this calculator does
The World Health Organization publishes two reference formulations for alcohol-based handrub, designed to be made locally where commercial product is unavailable. Both are specified for a 10 litre batch, which this scales to whatever volume you need.
The proportions matter more than they look. The ethanol formulation uses 833.3 mL of 96 per cent ethanol per 1,000 mL of finished product, which lands the final alcohol concentration in the effective range. Diluting further to stretch a batch defeats the purpose entirely.
The formula
Each ingredient in the WHO 10 litre reference recipe is scaled proportionally to the batch size requested, with water making up the remainder.
| Term | Meaning |
|---|---|
| Alcohol-based handrub | The WHO term for the product these formulations produce. |
| Hydrogen peroxide | Included to inactivate bacterial spores in the solution itself, not as a skin agent. |
| Glycerol | A humectant included to reduce skin drying. |
The inputs explained
| Field | What to enter |
|---|---|
| Batch size (mL) | The finished batch size in millilitres. |
| Alcohol type | Which WHO formulation to use. Formulation I uses ethanol, formulation II isopropyl alcohol. |
When to use it
Making handrub where supply is unavailable
The formulations exist for exactly that situation.
Scaling a published recipe
The WHO reference is specified in 10 litre batches, which few people need.
Understanding what is in commercial product
The formulation shows what each component is actually for.
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.
What does each batch size need?
Three batch sizes with proportional ingredients.
Questions
Why is the alcohol concentration so critical?
Because effectiveness depends on it. The WHO formulations land at roughly 75 to 80 per cent alcohol in the finished product, and diluting below about 60 per cent substantially reduces effect. Adding extra water to stretch a batch makes it considerably less useful.
What is the hydrogen peroxide for?
To inactivate bacterial spores that may be present in the solution itself. It is a preservative for the product rather than an active ingredient acting on your hands.
Can I use vodka or rubbing alcohol from a shop?
Vodka is typically 40 per cent alcohol, which is far too weak and cannot be concentrated at home. Isopropyl rubbing alcohol at 99.8 per cent works with formulation II; lower-strength versions will not reach the required final concentration.
Is homemade handrub as good as commercial?
Made exactly to the formulation with correct-strength ingredients, it meets the same specification, which is why WHO publishes it. Soap and water remains preferable whenever hands are visibly soiled.
For safe exposure limits in another domain, see the noise exposure time calculator. For a general health baseline, see the BMI calculator.