Calculator Inputs
Enter the stock bleach strength, target strength, and batch size. The calculator supports percent and ppm targets.
Formula Used
The calculator uses the standard dilution relationship:
C1 × V1 = C2 × V2
- C1 = stock sodium hypochlorite concentration
- V1 = stock solution volume required
- C2 = desired final concentration
- V2 = final prepared batch volume
Target conversion: Target % = ppm ÷ 10,000
Adjusted final volume: Final volume × (1 + allowance ÷ 100)
Stock solution needed: (Target % ÷ Stock %) × Adjusted final volume
Water needed: Adjusted final volume − Stock solution needed
Dilution factor: Stock % ÷ Target %
Estimated active sodium hypochlorite mass assumes a water-like dilute solution. Real products can vary with density, additives, age, and manufacturer specification.
How to Use This Calculator
- Enter the sodium hypochlorite stock concentration shown on the product label.
- Select whether your target strength is given in ppm or percent.
- Enter the desired target concentration.
- Enter the final batch volume and choose the unit.
- Add an allowance percentage when you expect spill, transfer, or line loss.
- Choose the number of decimal places for reporting.
- Press Calculate Mixing Ratio to show the result above the form.
- Use the CSV or PDF buttons to save the result.
Example Data Table
| # | Stock Strength | Target | Final Volume | Allowance | Stock Needed | Water Needed |
|---|---|---|---|---|---|---|
| 1 | 5.25% | 500 ppm | 1.00 L | 0% | 9.52 mL | 990.48 mL |
| 2 | 10.00% | 0.10% | 20.00 L | 5% | 210.00 mL | 20.79 L |
| 3 | 12.50% | 200 ppm | 5.00 gal | 0% | 30.28 mL | 18.90 L |
Safety Note
Sodium hypochlorite solutions can irritate skin, eyes, and lungs. Use suitable protective equipment and good ventilation while preparing working solutions.
Never mix bleach with acids, ammonia, or unknown cleaners. Always follow the product label, SDS, site policy, and local chemical handling rules.
Frequently Asked Questions
1. What does this calculator compute?
It calculates how much stock sodium hypochlorite and water you need to prepare a final batch at a chosen concentration. It also shows dilution factor, estimated active chemical, stock-to-water ratio, and a chart.
2. Can I enter the target in ppm instead of percent?
Yes. Choose the ppm mode and enter the desired value. The calculator converts ppm to percent using the relationship 1% = 10,000 ppm, then applies the dilution formula automatically.
3. Why must the target concentration be below the stock concentration?
A dilution lowers concentration. If your target is stronger than the stock solution, water cannot achieve that result. You would need a stronger stock product or a different preparation approach.
4. What does the extra allowance percentage do?
Allowance increases the prepared volume to cover expected losses during transfer, filling, spraying, or line priming. This helps you still deliver the intended usable volume after minor handling waste.
5. Is ppm always exact for bleach solutions?
PPM here is treated as a practical water-like approximation for dilute solutions. Real products can differ because density, formulation, temperature, age, and available chlorine content vary between manufacturers.
6. What does the dilution factor mean?
The dilution factor compares stock concentration to final concentration. For example, 1:100 means the final solution is one hundred times weaker than the stock concentration on the same percentage basis.
7. Can I use gallons or milliliters?
Yes. Select liters, milliliters, or US gallons. The calculator converts everything internally and returns the stock and water volumes in your chosen display unit for easier batching.
8. Should I rely only on this calculator for sanitation procedures?
Use it as a planning tool, not a substitute for label directions or regulatory guidance. Always follow site protocols, product instructions, compatibility rules, and chemical safety requirements for your application.