How It Works
This calculator works in 4 steps.
Enter the bleach strength
Type the sodium hypochlorite percent on the bottle.
Choose the instruction
Select the product label direction, or the CDC 5 tbsp per gallon direction for bottles without one.
Enter the batch size
Type the water volume in quarts, gallons, or liters.
Read the amounts
The calculator returns bleach in tsp, tbsp, cups, and mL, and the approximate ppm.
The Formula
The formula multiplies the bleach volume by its percent and divides by the total volume to estimate ppm.
V_bleach = rate × V_waterppm ≈ V_bleach × (% NaOCl) × 10,000 / (V_bleach + V_water)1 tbsp = 3 tsp = 14.79 mL; 1 cup = 16 tbsp- rate:
- Label or CDC amount per unit of water
- % NaOCl:
- Sodium hypochlorite percent on the label
- V_water:
- Water volume
5 tablespoons (73.9 mL) of 6% bleach in 1 US gallon (3,785 mL) of water gives about 73.9 × 6 × 10,000 / 3,859 ≈ 1,150 ppm sodium hypochlorite.
Conversion Table
The conversion table gives the approximate sodium hypochlorite level of the CDC recipes for 4 bleach strengths.
| Bleach strength | Gallon recipe | Approx. ppm | Quart recipe | Approx. ppm |
|---|---|---|---|---|
| 5.25% | 5 tbsp (73.9 mL) per 1 US gal | 1,006 ppm | 4 tsp (19.7 mL) per 1 US qt | 1,071 ppm |
| 6% | 5 tbsp (73.9 mL) per 1 US gal | 1,149 ppm | 4 tsp (19.7 mL) per 1 US qt | 1,224 ppm |
| 7.5% | 5 tbsp (73.9 mL) per 1 US gal | 1,437 ppm | 4 tsp (19.7 mL) per 1 US qt | 1,531 ppm |
| 8.25% | 5 tbsp (73.9 mL) per 1 US gal | 1,580 ppm | 4 tsp (19.7 mL) per 1 US qt | 1,684 ppm |
Approximate values assume labeled strength; bleach loses strength over time. Follow the product label first.
What Is the Bleach Dilution Calculator?
The Bleach Dilution Calculator is a tool that applies product-label or public-health dilution instructions to household bleach and returns the bleach and water amounts plus the approximate sodium hypochlorite level in ppm. When the bottle has no directions, CDC guidance for disinfecting is 5 tablespoons (1/3 cup) of bleach per gallon of room-temperature water, or 4 teaspoons per quart.
Household bleach is sold at different strengths, commonly 5.25% to 8.25% sodium hypochlorite. The same tablespoon amount gives a higher ppm with stronger bleach, so the calculator asks for the label percent. CDC advises making a fresh solution each day and never mixing bleach with ammonia or other cleaners.
Common Uses
There are 5 main uses of this calculator.
Household disinfection
Users prepare bleach solutions for hard, nonporous surfaces.
Childcare settings
Staff prepare daily bleach solutions per state guidance.
Food-contact sanitizing
Kitchens prepare lower-strength sanitizer per the label.
Spill cleanup
Labs prepare bleach for biological spill cleanup per their biosafety plan.
Outbreak response
Facilities scale batches for larger areas.