Dilution Calculator
To mix a ratio such as 1:10, add the parts together (1 + 10 = 11) and divide the amount you want by that number. For a 1 L sprayer that is 91 mL of concentrate and 909 mL of water, not 100 mL. Use the calculator below for ratios, mL per litre, per cent, sanitiser ppm and per hectare label rates. It also checks that your sprayer can take the mix.
Safety first. The product label and Safety Data Sheet (SDS) come first. Add acid to water, never water to acid. Never mix bleach with acids or ammonia.
Free tool
How much concentrate do I add?
Turn the rate on the label into millilitres for your sprayer, then check your sprayer can take the mix.
1:10 in a 1 L bottle is about 91 mL of concentrate and 909 mL of water. The calculator needs JavaScript to work out other mixes.
3. Check your sprayer can take it (optional)
A guide to the maths only. The product label and Safety Data Sheet (SDS) come first. Check strengths with the supplier of your chemical.
How to work out a dilution ratio
A ratio of 1:10 means 1 part concentrate and 10 parts water, so 11 parts in total. Divide the amount of mix you want by the total parts to get the concentrate. The rest is water.
- Concentrate = amount of mix ÷ (1 + parts of water)
- Water = amount of mix minus the concentrate
Example: a 1:20 mix for a 16 L backpack sprayer is 16,000 mL ÷ 21 = 762 mL of concentrate and 15.24 L of water.
Some labels write “1 in 20” instead. That means 1 part in 20 parts in total, so 50 mL in 1 L, the same as a 1:19 ratio. If a label is unclear, ask the supplier of the chemical.
Dilution ratio chart for common sprayer sizes
Millilitres (mL) of concentrate for each ratio and sprayer size. Top up with water to the size shown.
| Ratio | 1 L | 1.5 L | 5 L | 8 L | 16 L |
|---|---|---|---|---|---|
| 1:5 | 167 | 250 | 833 | 1,333 | 2,667 |
| 1:10 | 91 | 136 | 455 | 727 | 1,455 |
| 1:20 | 47.5 | 71.5 | 238 | 381 | 762 |
| 1:30 | 32.5 | 48.5 | 161 | 258 | 516 |
| 1:40 | 24.5 | 36.5 | 122 | 195 | 390 |
| 1:50 | 19.5 | 29.5 | 98 | 157 | 314 |
| 1:100 | 9.9 | 15 | 49.5 | 79 | 158 |
| 1:200 | 5 | 7.5 | 25 | 40 | 79.5 |
From 10 to 100 mL the amounts are rounded to the nearest half millilitre. Use a measuring cylinder or syringe for small amounts.
Converting mL per litre, per 100 litres and per cent
Many labels give an amount per litre of water, such as 20 mL per litre. Add that amount to each litre of water. A per cent works on the finished mix, so 5% of 8 L is 400 mL.
| Per litre of water | Ratio | Per cent | Per 100 L of water |
|---|---|---|---|
| 5 mL | 1:200 | 0.498% | 500 mL |
| 10 mL | 1:100 | 0.99% | 1 L |
| 20 mL | 1:50 | 1.96% | 2 L |
| 50 mL | 1:20 | 4.76% | 5 L |
| 100 mL | 1:10 | 9.09% | 10 L |
Bleach and chlorine sanitiser: mixing to a ppm
ppm means parts per million, and 1% is 10,000 ppm. For a chlorine sanitiser, mL of concentrate = litres of mix × ppm ÷ (strength % × 10).
The FSANZ cleaning and sanitising fact sheet gives 100 ppm chlorine for cold water and 50 ppm for warm water. That is 10 mL of commercial bleach (about 10%) or 25 mL of household bleach (about 4%) in 10 L of cold water. The table gives millilitres (mL) of bleach.
| Bleach strength | 100 ppm 1 L |
100 ppm 10 L |
50 ppm 1 L |
50 ppm 10 L |
|---|---|---|---|---|
| 4% | 2.5 | 25 | 1.3 | 12.5 |
| 10% | 1 | 10 | 0.5 | 5 |
| 12.5% | 0.8 | 8 | 0.4 | 4 |
Make sanitiser fresh each day and throw out what is left. Test strips confirm the strength. For quat and peracetic acid sanitisers, use the ppm and strength on that product's label. Bleach needs an EPDM sealed sprayer or a model rated for bleach: see our bleach resistant sprayers and food grade sanitising equipment.
Acid wash and acid etching concrete: work out your mix
Acid etching mixes, dwell times and neutralisers belong to the acid maker, so take the ratio from your acid's label and SDS. Enter that ratio and the acid's strength in the calculator. It shows the amounts and the strength of acid in your sprayer.
For example, a 32% hydrochloric acid mixed 1:10 is 2.91% acid in the sprayer. Our acid resistant sprayers (VITON seals) are rated for hydrochloric acid up to 10%. Always add the acid to the water, work in small sections, rinse before it dries, and keep runoff out of stormwater drains. More in our guide to acid etching concrete with a sprayer.
Knapsack and hand sprayers: label rates per hectare
Weed and crop labels often give a rate per hectare. How much goes in one tank depends on how much your sprayer puts out, so do a quick test first.
- Fill the sprayer with water only.
- Mark out an area, for example 5 m by 10 m (50 m²).
- Spray it at your normal walking pace and pressure, then measure the water you used.
- Litres per hectare = litres used ÷ area in m² × 10,000. Using 1.2 L over 50 m² is 240 L per hectare.
- Product per tank = label rate per hectare × tank size ÷ litres per hectare.
Example only, not a rate for any product: a label rate of 2 L per hectare, a sprayer putting out 200 L per hectare and a 15 L tank gives 150 mL of product per tank. Always use the rate on your product's label for your weed, crop and situation, and test again if you change the nozzle, pressure or pace. For labels that give an amount per 100 L of water, use the mL per litre option. More in our guide to knapsack sprayers for weed control. Before you spray, check the weather with our Delta T Calculator.
Check your sprayer can take the mix
Seals fail when the chemical is wrong for them. The calculator checks the strength in your sprayer against our Chemical Compatibility Guide, which is built from manufacturer resistance lists. In short, acids and petroleum solvents need VITON seals, and alkalis, bleach and caustic cleaners need EPDM. Check strong or unusual chemicals in the guide, or send us the SDS.
Selling a chemical? We supply the matching sprayer with your own label. Talk to us about custom labelling, or apply for a trade account.
Frequently asked questions
How do you calculate a dilution?
Add the parts of the ratio together, then divide the amount of mix you want by that total. That gives the concentrate, and the rest is water. For 1:10 in 1 L: 1,000 mL ÷ 11 = 91 mL of concentrate and 909 mL of water.
How much concentrate is a 1:10 dilution in 1 litre?
About 91 mL of concentrate and 909 mL of water. A 1:10 mix is 1 part concentrate to 10 parts water, so divide 1,000 mL by 11.
Is 1:10 the same as 10%?
No. A 1:10 mix is 1 part in 11, which is about 9.09%. A 10% mix is 1 part in 10, which is the same as 1:9.
How much is a 1:40 dilution?
1 part concentrate to 40 parts water, so 41 parts in total. That is 24.5 mL of concentrate in 1 L, or 122 mL in 5 L.
How much water do I add for a 1:20 dilution?
20 parts water for every part of concentrate, so 2 L of water for each 100 mL of concentrate. To fill a 5 L sprayer, use 238 mL of concentrate and 4.76 L of water.
What does 1 in 20 mean on a label?
1 part concentrate in 20 parts of finished mix, so 50 mL in 1 L. It is the same as a 1:19 ratio.
How much bleach do I need for a 100 ppm sanitiser?
In 10 L of cold water, FSANZ gives 10 mL of commercial bleach (about 10%) or 25 mL of household bleach (about 4%). For other strengths, mL of bleach = litres × ppm ÷ (strength % × 10).
What is the mix ratio for acid wash concrete?
Use the ratio on your acid's label and SDS, because it changes with the acid's strength, the concrete and the job. Enter that ratio and the acid's strength in the calculator to get the amounts and the strength in the sprayer. For example, a 32% hydrochloric acid mixed 1:10 is about 2.91% acid. Always add acid to water.
Can I mix bleach and acid in the same sprayer?
No. Bleach with an acid, or bleach with ammonia, gives off toxic gas. Keep separate sprayers, label them, and rinse well between products. Bleach and acids also need different seals.
How do I convert a per hectare label rate for a knapsack?
Test your sprayer to find the litres it puts out per hectare. Then product per tank = label rate per hectare × tank size ÷ litres per hectare. As an example only, 2 L per hectare at 200 L per hectare is 150 mL in a 15 L tank.