Free tool
Lawn application rate calculator
Put in the size of your lawn and the rate on the label. It tells you how much to measure out, area by area, and for a liquid it works out the water and the tank loads too.
Your lawn
Only know the sides?
What you are putting down
Put in an area and a rate, and the amount appears here.
Which number belongs to what
Getting this wrong is the usual reason a lawn ends up striped. Three numbers are involved and they come from three different places.
- The dose comes from the label
- Grams or millilitres per unit of area. It is the only part that decides how much product the grass actually receives.
- The water comes from your sprayer
- It depends on the nozzle, the pressure and your walking pace, so it has to be measured rather than read off a bottle. Water spreads the dose evenly; it does not change the dose.
- The ceiling, if there is one, comes from the label again
- Some products say not to exceed a certain strength in the tank. That is the one rule that ties the other two together, and the fix for breaching it is more water, never less product.
Questions people ask
- What is an application rate?
- The amount of product the label tells you to put on a given area, such as 30 grams per square metre or 200 millilitres per 100 square metres. Multiply it by the area you are treating and you have the amount to measure out.
- How much water do I mix it with?
- The label fixes the dose per area. How much water carries it is a property of your sprayer and how fast you walk, which is why the same dose can go on in 10 litres or 15 and both are correct. Measure your own sprayer once and use that figure.
- How do I measure what my sprayer puts down?
- Fill it with plain water, note the level, and cover a marked patch of 10 by 10 metres at your normal pace and pressure. Whatever you used is your output for every 100 square metres.
- What if the label sets a maximum concentration?
- That is the one thing that ties the dose and the water together. Enter it and the calculator tells you whether your tank would be too strong, and the least water that dose may go in.
- Do I need an account?
- No. This page works without one. An account saves your lawn's measured sections and your products, so the areas and rates fill themselves in.
Stop typing your lawn size in
Trace your lawn once from the satellite view and every section is measured for you. Record what is in your shed and the rates fill themselves in. Free, and it also builds the schedule around your grass, your season and your weather.