Dilution Ratio Calculator
This dilution ratio calculator turns a concentrate-to-diluent ratio like 1:8 into exact amounts. Enter the two parts of your ratio, tell it which volume you already know — the total you want to make, the concentrate you have, or the diluent you have — and type that amount. The other two amounts fill in instantly. It works with any unit you type (ml, oz, gallons, litres, drops) because the math itself never depends on units — you just add a label for the display.
What Is a Dilution Ratio?
A dilution ratio expresses how much concentrate to mix with how much diluent, written as two numbers like 1:8 or 1:32. The first number is the concentrate's share of the ratio, the second is the diluent's share, and together they describe the total "parts" that make up the finished mix — a 1:8 ratio is 9 total parts (1 concentrate + 8 diluent). What is a 1 to 5 dilution, for example? It's 1 part concentrate to 5 parts diluent — 6 total parts, so the concentrate makes up 1/6 of the final volume. The ratio itself never changes with scale: 1:8 describes the same mix whether you're making 90 ml or 90 litres.
How to Calculate a Dilution Ratio
The calculator mirrors how you'd actually work it out by hand. First, add the two ratio parts together to get the total parts. Then, depending on which amount you already know:
- You know the total amount you want to make — each of concentrate and diluent is the total multiplied by its share of the total parts.
- You know how much concentrate you have — diluent is the concentrate scaled up by the ratio (diluent parts ÷ concentrate parts), and total is the sum.
- You know how much diluent you have — concentrate is the diluent scaled down the same way, and total is the sum.
Tap the matching pill under "I know the" — Total amount, Concentrate, or Diluent — type that one number into Known amount, and both other figures update as you type. There's nothing to submit and nothing uploaded; it recalculates on every keystroke, right on your device.
Common Dilution Ratios by Use Case
A dilution ratio calculator gets used for a wide range of concentrates, and each field has its own typical range — always defer to the specific product's own label, since strength varies by formulation:
- Cleaning & disinfecting — household disinfectant dilutions (including diluted bleach) commonly land around 1:10 to 1:50 depending on the surface and contact-time needed.
- Herbicide & pesticide mixing — lawn and garden concentrates like glyphosate weed killers are typically mixed somewhere in the 1:20 to 1:50 range per the product label, often expressed as an amount per gallon of water.
- Car detailing — all-purpose cleaners, wheel cleaners, and foam shampoos ship as concentrates with their own printed dilution ratio chart, ranging from roughly 1:4 for heavy-duty jobs to 1:20 or weaker for light maintenance.
- Essential oils — topical blends for adult skin use are often diluted around 1:20 to 1:50 (roughly 2–5% essential oil in a carrier), with lower concentrations used for children or sensitive skin.
The same tool works just as well for less common concentrate math — darkroom developer and stop-bath dilutions, hydroponic nutrient concentrates, or scaling a drink concentrate to taste — any time you have a ratio and one known amount.
Dilution Ratio Chart Reference
For a quick reference, here's how much concentrate a few common ratios need to make 1 litre (1,000 ml) of total solution. Use the calculator above for any ratio or volume not listed — including gallons, ounces, or any other unit.
| Ratio | Concentrate share | Concentrate per 1 L total |
|---|---|---|
| 1:4 | 20% | 200 ml |
| 1:8 | 11.1% | 111 ml |
| 1:10 | 9.1% | 91 ml |
| 1:16 | 5.9% | 59 ml |
| 1:20 | 4.8% | 48 ml |
| 1:32 | 3.0% | 30 ml |
| 1:40 | 2.4% | 24 ml |
| 1:64 | 1.5% | 15 ml |
| 1:128 | 0.8% | 8 ml |
| 1:256 | 0.4% | 4 ml |
Frequently Asked Questions
How do you calculate a dilution ratio?
Add the two parts of the ratio together to get the total parts, then divide whichever amount you know by its share of that total. For a 1:8 ratio (9 total parts) making 900 ml, concentrate is 900 × (1/9) = 100 ml and diluent is 900 × (8/9) = 800 ml. This calculator does that division for you — enter the ratio and one known amount and it solves the other two instantly.
What does a dilution ratio like 1:5 actually mean?
A 1:5 dilution ratio means 1 part concentrate to 5 parts diluent — 6 total parts, so the concentrate makes up 1/6 (about 16.7%) of the final mix. It does not mean "5 times weaker" in a simple sense; it means for every unit of concentrate you use, you add 5 units of diluent alongside it, not instead of it.
What's the correct bleach dilution ratio for disinfecting?
A common household disinfecting dilution is roughly 1:50 (about 1 part bleach to 50 parts water), though the right ratio depends on the bleach concentration and the surface being disinfected — always check the product label first. Once you know the ratio, enter it here along with how much total solution you want to make, and the calculator gives you the exact bleach and water amounts.
What's the right Roundup mixing ratio per gallon?
Roundup and similar glyphosate concentrates list a mixing ratio on the product label — it varies by formulation and target weed, often somewhere around 1:20 to 1:50 for general use. Read your specific bottle's label for the correct ratio, then use this calculator with "I know the: Total amount" set to one gallon (or however much spray you're mixing) to get the exact concentrate and water split.
What dilution ratio do detailers use for car-cleaning chemicals?
Detailing chemicals like all-purpose cleaners, wheel cleaners, and snow foam are typically sold as concentrates with a printed dilution ratio chart, commonly ranging from about 1:4 for heavy-duty use down to 1:20 or more for light maintenance washes. Check your product's own chart for the ratio, then set "I know the" to whichever amount you're starting from — a full spray bottle or a set amount of concentrate — to get the rest instantly.
How much should I dilute essential oils for skin use?
Common topical dilution guidance for adults is around 2–5% essential oil in a carrier oil, which is roughly a 1:20 to 1:50 ratio of essential oil to carrier — always confirm with product guidance since safe ratios vary by oil and by person. Enter that ratio along with the amount of carrier oil or total blend you're making to see the precise drop-scale amounts.
