Dilution and Ratio Calculator.
Convert any dilution between ratio, ounces per gallon, millilitres per litre, percentage and ppm — for any concentrate.
What you are diluting
Start from a published dilution for a common job, or enter the one you already have in any of the ways it gets written.
Killing bacteria and viruses on a hard, non-porous surface that has already been cleaned.
5 tablespoons (one third of a cup) of bleach per US gallon of room-temperature water, or 4 teaspoons per US quart.
Household bleach runs 5% to 8.25% and the figure is on the front. Entering it gives the available chlorine in the finished mix, which is the unit food and health regulations are written in.
Anything else going into the same container
Tick everything that will share the bucket. A combination that releases a toxic gas or reacts violently is refused outright — no dose is shown for it, and each hazard cites CDC, EPA, ATSDR or OSHA.
A synthetic detergent blend. Formulations are proprietary and vary widely between products and between batches.
Dilute acetic acid, 5% in table strength and up to 30% in cleaning strength.
Ammonium hydroxide in water. Present in many glass and floor cleaners.
A flammable alcohol solvent, typically sold at 70% or 91%.
An oxidising solution, 3% in household strength.
A cationic disinfectant registered with the EPA and used at a specific labelled concentration.
The standard approach, using widely available products.
The batch
Both questions are the same relation read in opposite directions, so either one is answered from the other.
US and Imperial gallons are both here on purpose. An Imperial gallon is 20% larger.
An injector dilutes the mix a second time on its way to the surface. With this on, the dilution above is read as the target on the surface and the jug mix is worked back from it.
Conventional
1:51.2 — 2.5 US fl oz per US gallon of water
For 1 gal of finished solution: 0.0192 gal of concentrate into 0.981 gal of water. At 6% sodium hypochlorite that works out at about 1,149 ppm available chlorine in the finished mix.
What you need
Sodium hypochlorite solution
also sold as chlorine bleach
0.0192 gal
Oxidising disinfectant and stain bleach.
Reading the label
The ingredients panel says "sodium hypochlorite" and the front of the bottle carries a percentage — ordinary household strength runs from about 5% to 8.25%. Scented, thickened, gel and splash-less products contain surfactants and thickeners as well, which changes both the dose and what the contents can safely meet, so plain unscented liquid is the only form these published dilutions describe.
Method
- Clean the surface first. Hypochlorite is consumed by organic soil, so a dirty surface uses up the chlorine before it disinfects anything.
- Measure the bleach into room-temperature water — not hot. Heat accelerates the decomposition of sodium hypochlorite, so hot water lowers the available chlorine rather than raising it.
- Apply so the surface stays visibly wet, and leave it wet for at least one minute of contact time unless the product label states longer.Then wait 1 min
- Rinse any surface that food, skin or a pet will touch, and let it air dry.
- Mix a fresh batch each day. A diluted bleach solution loses effectiveness after about 24 hours.
- Concentrate
- 0.0192 gal
- Water
- 0.981 gal
- Finished solution
- 1 gal
Every figure on this page is worked out from 1:51.2. Nothing here is specific to any brand of concentrate.
Every way to say this dilution
1:51.2
The same dilution, stated every way a label, a bottle or a trade sheet is likely to state it. Readings taken per volume of water and per volume of finished solution are listed separately, because they are different numbers.
- Ratio, concentrate to water
- 51.2 parts water to 1 part concentrate
- Percentage of the finished mix
- 1.92 %
- Parts per million of the finished mix
- 19,157 ppm
- Per US gallon of water
- 2.5 US fl oz
- Per finished US gallon
- 2.45 US fl oz
- Per Imperial gallon of water
- 3.13 Imperial fl oz
- Per litre of water
- 19.53 ml
- Per finished litre
- 19.16 ml
- Per US gallon of water, in cups
- 0.313 US cups
- Per US quart of water, in tablespoons
- 1.25 US tbsp
- Per US quart of water, in teaspoons
- 3.75 US tsp
The "make up to one gallon" reading. Always slightly less than the per-water figure.
An Imperial gallon is 4.546 L against a US gallon of 3.785 L — 20% larger — and an Imperial fluid ounce is 4% smaller than a US one.
A US cup is 236.6 ml; a metric cup is 250 ml.
A US tablespoon is 14.79 ml, a metric one 15 ml and an Australian one 20 ml.
Worth knowing
Mix hypochlorite into room-temperature water
Heat accelerates the decomposition of sodium hypochlorite. Mixing bleach into hot water drives off chlorine and leaves less available chlorine in the bucket, not more, so a hot mix is weaker than the same dose in room-temperature water. Published dilutions assume room-temperature water. A diluted solution also loses effectiveness after about 24 hours regardless of temperature, so it is mixed fresh each day.
CDC — Cleaning and disinfecting with bleach — https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
Worth knowing
This mix computes to about 1,149 ppm available chlorine
At 6% sodium hypochlorite this dilution is above the 50–100 ppm band the FDA Food Code sets for sanitising food-contact surfaces. That is expected for a disinfecting or mould mix, which is rinsed off; it is too strong for a surface food will touch. Bleach also loses strength on the shelf, so the only way to confirm a sanitising mix is a chlorine test strip.
FDA Food Code — chemical sanitising of food-contact surfaces — https://www.fda.gov/food/retail-food-protection/fda-food-code
Do not mix these. No result is shown.
Do not combine ingredients from different columns. Each option below is safe used on its own.
This combination is known to produce a hazardous reaction, so this tool will not build a recipe or a method from it. Choose different ingredients and the result will appear.
- Can be fatalChlorine gas
Acid liberates chlorine gas from hypochlorite bleach. Chlorine gas burns the eyes, throat and lungs, causes fluid to collect in the lungs hours after exposure, and can be fatal in an enclosed space.
CDC / NIOSH Pocket Guide to Chemical Hazards — Chlorine(opens in a new tab)
| Compared on | Conventional | Natural |
|---|---|---|
| Effectiveness | Effectiveness: StrongSource noted in the assumptions below. | Effectiveness: WeakSource noted in the assumptions below. |
| Active time | ~2 min active | ~2 min active |
| Safety notes | Ventilate. Never combine with acid, ammonia, alcohol or any other cleaner.Source noted in the assumptions below. | Low inhalation risk at 5%. Never combine with bleach — the pair releases chlorine gas.Source noted in the assumptions below. |
| Surface risk | CautionSource noted in the assumptions below. | NeverSource noted in the assumptions below. |
| Availability | Common | Common |
| Septic safe | ConditionalSource noted in the assumptions below. | Yes |
Cells marked with a dagger carry a source note, listed under “How this is worked out” below.
How this is worked out
- What a ratio means here
- 1:32 is one part concentrate to thirty-two parts WATER, giving thirty-three parts of finished solution. Read as "make up to" instead, the same ratio is one part in thirty-three. Both readings are shown because product labels use both and rarely say which.
- Ratio to percentage
- percent = 100 / (1 + parts of water). 1:32 is 100/33 = 3.0303% of the finished mix. Parts per million is the same figure times 10,000.
- Dose per volume of water
- concentrate = water volume / parts of water. Per finished volume it is finished volume / (1 + parts of water). At 1:32 that is 4 US fl oz into a US gallon of water, or 3.88 US fl oz in a finished US gallon.
- US gallon
- Exactly 231 cubic inches, which is 3.785411784 L, from the definition of the inch.Source: International yard and pound agreement, 1959
- Imperial gallon
- Exactly 4.54609 L — about 20% larger than a US gallon. An Imperial fluid ounce is 28.4130625 ml against a US fluid ounce of 29.5735295625 ml, so it is about 4% smaller. Both differences are large enough to ruin a batch, which is why no unit in this tool is called simply "gallon".Source: Weights and Measures Act 1985
- Spoons and cups
- US tablespoon 14.78676478125 ml, metric tablespoon 15 ml, Australian tablespoon 20 ml. US cup 236.5882365 ml, metric cup 250 ml. Every figure above is the exact definition rather than a rounded one, so a conversion out and back returns the number you started with.
- This dilution
- 5 tablespoons (one third of a cup) of bleach per US gallon of room-temperature water, or 4 teaspoons per US quart.
- Source for chlorine bleach, household disinfection
- This is the household disinfecting strength. It is roughly fifteen times stronger than the mix used to sanitise a food-contact surface, and it is meant to be rinsed off anything food touches.Source: CDC — Cleaning and disinfecting with bleach — https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
- Available chlorine
- ppm = concentrate percentage x 10,000 / (1 + parts of water). At 6% and 1:51.2 that is 1,149 ppm in the finished mix. Household bleach is 5% to 8.25% and loses strength on the shelf, so this is an upper bound on a fresh bottle rather than a measurement.Source: FDA Food Code — chemical sanitising of food-contact surfaces — https://www.fda.gov/food/retail-food-protection/fda-food-code
- Chlorine bleach, household disinfection — published dose
- 5 tablespoons (one third of a cup) of bleach per US gallon of room-temperature water, or 4 teaspoons per US quart.Source: CDC — Cleaning and disinfecting with bleach — https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
- White vinegar solution — published dose
- Equal parts 5% white vinegar and water, which is a 1:1 dilution.Source: No published standard exists for this class. The figure shown is the middle of the range printed on ordinary consumer and trade labels; the label on the container in your hand overrides it.
- How the two columns compare
- Effectiveness on this row means disinfection specifically. Vinegar is not a disinfectant in the regulatory sense: no plain vinegar holds an EPA registration, so it makes no kill claim and it does not sanitise. It is included because it is what people search for, and the honest answer is that it cleans well and disinfects poorly.
- Advisory — respiratory
- Hypochlorite gives off chlorine slowly on its own, which is why bleach smells. Use it with a window open or extraction running, and never in a closed bathroom.Source: CDC / NIOSH Pocket Guide to Chemical Hazards — Chlorine — https://www.cdc.gov/niosh/npg/npgd0115.html
- Advisory — surfaces
- Bleach corrodes stainless steel, aluminium and natural stone, and permanently removes colour from fabric and grout dye.Source: OSHA Occupational Chemical Database — https://www.osha.gov/chemicaldata
- Advisory — surfaces
- Acetic acid etches marble, limestone, travertine and unsealed grout permanently, and dulls waxed and oiled wood finishes.Source: US EPA — Safer Choice ingredient criteria — https://www.epa.gov/saferchoice
- Why no cost is shown
- No price appears anywhere in this tool. Concentrate prices are regional, move with pack size, and quoting one would amount to recommending a product. What is shown instead is the volume of concentrate a batch consumes, which does not vary.
- Rounding
- Figures are rounded for someone holding a measuring jug: whole units above 1,000, two decimals in the ordinary range, and three significant figures below one. Conversions are computed at full precision and rounded only for display, so nothing compounds.
What each comparison row means
- Effectiveness
- How well this option performs on the specific job selected above — not a general rating of the product.
- Active time
- Hands-on time only. Soaking, dwelling and drying time are listed separately in the method, not here.
- Safety notes
- Skin, respiratory, child and pet considerations. Descriptive — read it rather than scoring it.
- Surface risk
- Whether this option can damage the surface it is used on. "Never" means it causes permanent damage.
- Availability
- Whether you can buy this at an ordinary supermarket or hardware store, or need a specialist supplier.
- Septic safe
- Whether this is safe to send down the drain on a septic system. "Conditional" means it depends on volume or dilution.
Source notes
- CDC — Cleaning and disinfecting with bleach — https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
- CDC / NIOSH Pocket Guide to Chemical Hazards — Chlorine — https://www.cdc.gov/niosh/npg/npgd0115.html
- Hypochlorite corrodes stainless steel, aluminium and natural stone, and permanently removes dye from fabric and grout.
- Small household volumes of diluted hypochlorite are generally tolerated; repeated large volumes suppress the bacterial population a septic tank depends on.
- Weak on this row because the row measures disinfection. Only EPA-registered products may make a kill claim, and no plain vinegar is registered. On general cleaning vinegar performs well.
- Acetic acid etches marble, limestone, travertine and unsealed grout permanently, and dulls waxed and oiled wood.