Weedicide (knapsack) Spray Dilution Calculator
Work out exactly how much weedicide (knapsack) to add per sprayer tank and for the whole field, from the label dose per acre and your spray volume.
Walk at a steady pace with an even swath, use a flood-jet or flat-fan nozzle for herbicides, and keep this sprayer for weedicides only.
Always follow the product label — the label is the law. Verify doses, PHI and compatibility with the manufacturer and local regulations before spraying.
Farmers and spray operators use the free Weedicide (knapsack) Spray Dilution Calculator to mix the correct amount per tank — avoiding the under-dosing that wastes a spray and the over-dosing that wastes money, harms the crop and breaches residue limits.
About Weedicide (knapsack) Spray Dilution Calculator
Getting pesticide dilution right is the difference between control and a wasted, possibly harmful spray. For knapsack weed spraying, mix the per-acre herbicide dose into the number of tanks needed to cover one acre at ~150 L/acre. This calculator takes the label dose per acre, your spray volume per acre and your tank size, and works out how much weedicide (knapsack) to add to each tank, the total product for the field, the concentration per litre and the number of tank loads. The product label always takes precedence — doses here are typical values to plan with.
How to use Weedicide (knapsack) Spray Dilution Calculator
- 1Enter the label dose per acre and your spray volume per acre.
- 2Enter your sprayer tank size and the area to spray.
- 3Measure out the weedicide (knapsack) per tank shown and spray with full coverage and PPE.
Why use Weedicide (knapsack) Spray Dilution Calculator?
- ✓Converts the per-acre dose into a per-tank amount instantly
- ✓Gives total product, total water and tank loads for the field
- ✓Works for any tank size and spray volume
- ✓Free, instant and fully in-browser — works offline in the field
Frequently asked questions
How much weedicide (knapsack) do I add per litre of water?+
For knapsack weed spraying, mix the per-acre herbicide dose into the number of tanks needed to cover one acre at ~150 L/acre. The exact rate is on your product's label — divide the label dose per acre by your spray volume per acre to get the per-litre concentration, which this tool does for you.
How do I calculate weedicide (knapsack) per sprayer tank?+
Per-tank dose = label dose per acre × tank size ÷ spray volume per acre. For example, 800 ml/acre at 150 L/acre in a 15 L tank is about 80 ml per tank.
Why must I follow the label dose exactly?+
Walk at a steady pace with an even swath, use a flood-jet or flat-fan nozzle for herbicides, and keep this sprayer for weedicides only. Over-dosing breaches Maximum Residue Limits (MRLs) and can be illegal; under-dosing fails to control the pest and breeds resistance. The label is legally binding.
Is this tool free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline in the field and your data never leaves the device.
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