Disinfectant Dilution Ratio Calculator
Calculate how much concentrated disinfectant and water to mix to achieve your desired working concentration.
Formula
Uses the dilution equation C₁V₁ = C₂V₂:
- V₁ = (C₂ × V₂) / C₁
- Vwater = V₂ − V₁
Where:
- C₁ = stock (concentrate) concentration (%)
- C₂ = desired working concentration (%)
- V₁ = volume of concentrate required (mL)
- V₂ = total final volume required (mL)
Parts per million (ppm) conversion: ppm = % × 10,000
Assumptions & References
- Assumes the disinfectant is water-based with a density approximately equal to water (1 g/mL); for high-density concentrates, volume-based mixing may introduce minor error.
- The dilution equation C₁V₁ = C₂V₂ assumes ideal mixing with no volume contraction.
- ppm values assume weight/volume basis (mg active ingredient per litre of solution).
- Common reference concentrations: 200–500 ppm (0.02–0.05%) for food-contact surfaces; 1,000 ppm (0.1%) for general disinfection; 5,000 ppm (0.5%) for blood/body-fluid spills (WHO, CDC guidelines).
- Always add disinfectant to water (not water to disinfectant) to minimise splashing of concentrate.
- Reference: WHO (2020) Cleaning and disinfection of environmental surfaces in the context of COVID-19; CDC Guidelines for Disinfection and Sterilization in Healthcare Facilities.