# Bleach Dilution Calculator

Calculate the exact amount of bleach to add to water for any desired ppm concentration. Supports household and industrial bleach.

## What this calculates

Calculate the exact volume of bleach needed to make a solution at your desired concentration in ppm. Supports regular household bleach (5.25%), ultra bleach (8.25%), and industrial concentrations. Uses the dilution formula C₁V₁ = C₂V₂.

## Inputs

- **Desired Concentration** (ppm) — min 1 — Target sodium hypochlorite concentration in parts per million (ppm). Common: 200 ppm for food-contact sanitizing, 1000 ppm for general disinfection, 5000 ppm for blood spills.
- **Desired Volume** (L) — min 0.01 — Total volume of diluted bleach solution needed in liters.
- **Bleach Stock Concentration** (% NaOCl) — min 0.1, max 15 — Sodium hypochlorite percentage of your bleach. Regular household: 5.25%, Ultra: 8.25%, Industrial: 10-12.5%.

## Outputs

- **Bleach Needed** (mL) — Volume of bleach stock to add.
- **Water Needed** (mL) — Volume of water to add.
- **Dilution Ratio** — formatted as text — Ratio of bleach to total solution.
- **Instructions** — formatted as text — Mixing instructions.

## Details

Proper bleach dilution is essential for effective disinfection without waste or safety risks. The active ingredient in bleach is sodium hypochlorite (NaOCl), and its concentration determines the antimicrobial effectiveness.

Common Concentrations

- 50-200 ppm: Food-contact surface sanitizing (FDA recommended)

- 500-1000 ppm: General household disinfection, bathroom surfaces

- 2000-5000 ppm: Blood and body fluid spills (CDC/WHO recommended)

- 5000-10000 ppm: Norovirus decontamination, high-risk areas

The Formula

C₁V₁ = C₂V₂, where C₁ is the stock bleach concentration (converted from % to ppm: 1% = 10,000 ppm), V₁ is the volume of bleach to add, C₂ is the desired ppm, and V₂ is the total volume.

Important Safety Notes

- Never mix bleach with ammonia (creates toxic chloramine gas) or acids (releases chlorine gas)

- Prepare fresh solutions daily as bleach degrades over time

- Stock bleach loses potency after opening; check the expiration date

- Use in well-ventilated areas and wear appropriate protective equipment

- Bleach is corrosive to metals, fabrics, and some surfaces at high concentrations

## Frequently Asked Questions

**Q: What concentration of bleach kills viruses?**

A: Most viruses are inactivated by 1000 ppm (0.1%) sodium hypochlorite with at least 1 minute of contact time. For harder-to-kill viruses like norovirus, the CDC recommends 5000 ppm (0.5%). HIV and most enveloped viruses are killed at much lower concentrations (200-500 ppm).

**Q: How long does diluted bleach last?**

A: Diluted bleach solutions lose effectiveness over time. Prepare fresh daily for critical applications. A properly stored 1000 ppm solution retains adequate strength for about 24 hours. Concentrated stock bleach lasts 6-12 months if stored in a cool, dark place in its original container.

**Q: What is the difference between regular and ultra bleach?**

A: Regular household bleach contains 5.25% sodium hypochlorite. Ultra or concentrated bleach contains 8.25%. Some industrial bleaches are 10-12.5%. When following dilution guides, always check your specific bleach concentration, as using the wrong percentage will give an incorrect final concentration.

**Q: Can I use bleach to purify drinking water?**

A: In emergencies, the EPA recommends adding 2 drops of regular unscented 5.25% bleach per liter of clear water (about 4 ppm), or 4 drops for cloudy water. Let stand 30 minutes before drinking. Do not use bleach with added fragrances, surfactants, or other additives for water purification.

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Source: https://vastcalc.com/calculators/chemistry/bleach-dilution
Category: Chemistry
Last updated: 2026-04-21