Enter the dose from the product label, your tank volume, the water rate you spray at and the size of the plot. You get the amount of product for one full tank, how many tank loads the job takes, what goes into the partial last tank, and the total product needed. The label always outranks this calculator — it converts your numbers, it does not recommend a dose.
Enter it exactly as printed, then pick the matching basis below.
Knapsack sprayers are usually 12–20 l; tractor tanks 300–1,000 l.
Litres of spray per hectare, from your own calibration.
Enter the label dose, tank volume, water rate and the area to spray.
How it works
Labels state a dose in one of two ways: per hectare (for example 2 l/ha) or as a concentration per 100 litres of water (for example 50 ml/100 l). The tool accepts either and converts internally to a per-hectare figure using your water rate, then works out everything else, so both bases give identical results for the same job. It also shows the dose in the other form, which is how you check a label against a neighbour’s advice or an older recommendation.
The water rate — litres of spray per hectare — is the number that ties the two together. One full tank covers tank volume ÷ water rate hectares, and the product for that tank is the per-hectare dose multiplied by that area. Total water is area × water rate, so the number of tank loads is total water ÷ tank volume, with the remainder shown separately: the last tank is normally partial, and it needs proportionally less product, not a full dose.
Areas can be entered in square metres, ari or hectares, so a 5-ar garden and a 5-hectare field use the same tool. Everything runs in your browser — no product database, no cloud lookup, nothing uploaded. Enter the dose in the unit printed on the label (ml, g, l or kg) and results come back in that same unit, with a conversion to litres or kilograms once the total exceeds 1,000.
Practical examples
A tractor sprayer over 5 hectares
A 2 l/ha dose at a 300 l/ha water rate with a 400 l tank: one tank covers 1.33 ha and takes 2.67 l of product. The job needs 1,500 l of water — three full tanks plus a 300 l last tank with 2 l of product — and 10 l in total.
A backpack sprayer in the garden
A label reading 50 ml/100 l with a 15 l knapsack means 7.5 ml per tank. Spraying 5 ari at 600 l/ha needs 30 l of water, so two full tanks and 15 ml of product altogether — the per-hectare equivalent is 300 ml/ha.
A job that divides evenly
Four hectares at 300 l/ha is exactly 1,200 l, which is three 400 l tanks with no remainder. The tool shows no partial tank, so you mix three identical loads.
A 250 m² vegetable bed
At a 500 l/ha water rate that bed needs only 12.5 l of spray. With a 10 l sprayer that is two loads, and a 2 l/ha dose works out to 50 ml of product for the whole bed.
Frequently asked questions
Which dose basis should I choose?
Whichever your label uses. Per-hectare doses are the norm for field crops; concentration per 100 litres is common for orchards, vineyards and garden products. Never convert one to the other by guessing a water rate — enter the rate you actually spray at.
What is a water rate and how do I find mine?
It is the litres of spray solution you apply per hectare, set by your nozzles, pressure and driving speed. Calibrate it: spray water over a measured area, note how many litres you used, then scale to a hectare. Field crops commonly run 200–400 l/ha, orchards considerably more.
How much product goes into the last, partial tank?
Proportionally less. The tool shows the litres of water left for that tank and the matching product amount, so the concentration stays the same as in the full tanks. Filling a partial tank with a full dose overdoses the crop and breaks the label rate.
Can I just mix a full tank and stop when the plot is done?
You can, but you are then left with surplus spray you must dispose of properly. Mixing only what the area needs is both cheaper and the reason this calculator shows the partial tank separately.
Does the dose change if I use less water per hectare?
The per-hectare dose stays the same; the concentration in the tank goes up. That is exactly why a label written per 100 litres depends on your water rate, and why the tool shows both forms side by side.
In what order should I fill the tank?
Half-fill with clean water and start the agitator, add the product, rinse the measuring vessel into the tank, then top up with water to the final volume. Never pour concentrate into an empty tank.
Can I mix two products in one tank?
Only if both labels allow that combination. Compatibility, order of addition and the total rate all matter, and this tool calculates one product at a time — run it once per product and check the labels for the mix.
What safety equipment do I need?
What the label specifies — typically gloves, eye protection, coveralls and a respirator for concentrate handling. Also respect wind limits, buffer zones near water, re-entry intervals and the pre-harvest interval, none of which any calculator can compute for you.
Does the tool know doses for specific products?
No, deliberately. Registered doses differ by product, crop, pest and country, and they change. Read the dose off the label in front of you and enter it.
Can I use it for foliar fertilizer or biological products?
Yes. Any product with a dose per hectare or per 100 litres works the same way, including foliar feeds, wetting agents and biologicals.
Why show the area one tank covers?
Because it is the practical figure while spraying: knowing one tank covers 1.33 ha tells you where to expect to refill, and it is the quickest way to spot that your water rate is off if the tank runs dry early.
Are my numbers sent anywhere?
No. The calculation happens in your browser and nothing about your plot or products leaves the device.
Related tools
Fertilizer Calculator
Turn a kg/ha nutrient target and an NPK grade into the fertilizer rate, total kilograms and bag count.
Agriculture & garden
Plant Spacing Calculator
How many plants fit your plot at a given row and in-row spacing, with density per m² and per hectare.
Agriculture & garden
Volume Converter
Convert between litres, millilitres, cubic metres, gallons, cups and spoons — instantly, in your browser.
Unit converters
Percentage Calculator
Calculate X% of a number, what percent one number is of another, and percentage change.
Everyday calculators
Seed Rate Calculator
Seeding rate in kg/ha from target plant density, thousand-seed weight, germination and purity.
Agriculture & garden
Irrigation Water Calculator
Water needed for an irrigation depth in litres and m³, plus the run time from drip or sprinkler rate.
Agriculture & garden