Bleach Dilution Calculator
Find exactly how much bleach to add to water for a sanitizing or disinfecting solution. Pick the strength on your bottle, the use or target ppm, and the amount of water: you get the answer in teaspoons, tablespoons, cups and milliliters.
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Look for “sodium hypochlorite …%” on the label
1:10 = 1 cup bleach + 10 cups water
How to use the Bleach Dilution Calculator
- Pick your bleach strength from the label (look for sodium hypochlorite %). Regular US bleach is usually 6% or 8.25% today.
- Choose the use, such as sanitizing food-contact surfaces or disinfecting hard surfaces, or type your own ppm. Switch to Ratio if your instructions say 1:10 or 1:100.
- Enter the amount of water and its unit (gallons, quarts, cups, fl oz, liters or mL).
- Press Calculate bleach amount to see the bleach in kitchen measures and mL, the final ppm and a table for other container sizes.
- Mix it safely: add the bleach to cool water, label the container and make a fresh batch every day.
Bleach dilution formula
Household bleach is a solution of sodium hypochlorite. Its strength in parts per million (ppm) of available chlorine is the label percentage times 10,000, so 6% bleach is about 60,000 ppm and 8.25% bleach is about 82,500 ppm. To reach a target strength when you add bleach to a known amount of water:
Bleach = Water × Target ppm ÷ (Bleach ppm − Target ppm)
Example: 1 gallon (3,785 mL) of water at 200 ppm with 6% bleach needs 3,785 × 200 ÷ (60,000 − 200) ≈ 12.7 mL, which is about 2½ teaspoons.
Bleach per gallon of water: quick reference
Amounts are rounded kitchen measures for 1 US gallon of water. Older 5.25% bleach needs about 15% more than 6% bleach; 8.25% bleach needs about 27% less.
| Target | Typical use | 6% bleach per gallon | 8.25% bleach per gallon |
|---|---|---|---|
| 50 ppm | Low end of food-contact sanitizing | ⅝ tsp (3.2 mL) | ½ tsp (2.3 mL) |
| 100 ppm | Sanitizing dishes and food-contact surfaces | 1¼ tsp (6.3 mL) | 1 tsp (4.6 mL) |
| 200 ppm | High end of food-contact sanitizing | 2½ tsp (12.7 mL) | 1⅞ tsp (9.2 mL) |
| 600 ppm | Non-food hard surfaces, toys (then rinse) | 2½ tbsp (38 mL) | 2 tbsp (28 mL) |
| 1,000 ppm | Disinfecting hard, non-porous surfaces | 4⅓ tbsp (64 mL) | 3 tbsp (46 mL) |
| 5,000 ppm | Body-fluid spills on hard surfaces | 1½ cups (344 mL) | 1 cup (244 mL) |
Tips for using bleach solutions
- Clean first, then sanitize or disinfect. Dirt and food residue use up chlorine, so wash with detergent and rinse before applying bleach solution.
- Respect the contact time. The surface must stay wet for the time on the product label (often 1 to 10 minutes) to work.
- Use plain, unscented bleach. Splash-less, scented and gel bleaches may be weaker or not registered for disinfecting.
- Check the date. Bleach slowly loses strength in the bottle, especially after several months or in heat, so an old bottle may be weaker than its label.
- Rinse food-contact surfaces if you use more than 200 ppm, and follow your local health code if you run a food business.
- Store safely. Keep diluted bleach in a labeled, closed container away from children and pets, and never in a food or drink bottle.
Frequently asked questions
How much bleach per gallon of water to sanitize?
For food-contact surfaces a common target is 50 to 200 ppm of available chlorine. With 6% bleach that is roughly 0.6 to 2.5 teaspoons per gallon; about 1 tablespoon per gallon of 6% bleach gives roughly 230 ppm, slightly above the top of that range. Always check the directions on your bleach label, since EPA-registered products list their own sanitizing ratios.
How much bleach per gallon of water to disinfect?
A widely used household disinfecting strength is about 1,000 ppm, which works out to roughly 4⅓ tablespoons (a generous 1/4 cup) of 6% bleach or 3 tablespoons of 8.25% bleach per gallon. The CDC's household recipe of 1/3 cup of 5.25–8.25% bleach per gallon lands between about 1,000 and 1,700 ppm. Use it on pre-cleaned, hard, non-porous surfaces and leave it wet for the contact time on the label.
What does ppm mean for bleach?
Parts per million of available chlorine. Bleach labeled 6% sodium hypochlorite contains about 60,000 ppm, so 1% equals 10,000 ppm. Diluting 6% bleach 1:59 (1 part bleach in 60 parts total) gives about 1,000 ppm.
What is the formula for diluting bleach?
Bleach volume = water volume × target ppm ÷ (bleach ppm − target ppm), where bleach ppm = percent × 10,000. This is C1V1 = C2V2 rearranged for adding bleach to a known amount of water, so the final mixture includes the bleach volume too.
What does a 1:10 bleach solution mean?
One part bleach mixed with ten parts water, for example 1 cup of bleach in 10 cups of water. With 6% bleach that gives about 5,450 ppm, a strong solution used for body-fluid spills on hard surfaces. Some instructions use 1:10 to mean 1 part in 10 total; check which one your source means.
How long does diluted bleach last?
Diluted bleach loses strength over time, faster in warm places, in sunlight and in open containers. Mix a fresh batch daily, keep it in a closed, labeled, opaque container and discard leftovers rather than storing them for weeks.
Can I mix bleach with vinegar or ammonia to make it stronger?
No. Bleach mixed with ammonia releases toxic chloramine gases and bleach mixed with vinegar or other acids releases chlorine gas. Only mix bleach with plain water and rinse surfaces between different cleaning products.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.