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Spray Calculator

Calculate sprayer tank loads, water volumes and product quantities from tank size, water rate, field area and label dose rate.

Responsible use

  • Use product rates from the approved label or your agronomist's recommendation.
  • This calculator helps with tank filling quantities only.
  • Always follow the product label, statutory conditions of use, buffer zones, stewardship guidance and operator requirements.

Label the job — these fields appear in copy and print.

Tank volume (clean water nominal fill) and water rate matching your label or application regime.

Rates are what you intend to spray per hectare. Quantities assume even coverage matching the stated water volume.

Product 1

Future versions may link product names to MyAgronomist product pages and tank-mix data — for now, enter free text. Check compatibility and mixing order separately (see Tank mix checker).

Results

Waiting for inputs

Enter a tank volume, water rate in L/ha, and field area (hectares) to calculate the tank plan and product quantities. Use positive numbers only — the calculator divides by tank size and water rate for you when those are valid.

  • Use product rates from the approved label or your agronomist's recommendation.
  • This calculator helps with tank filling quantities only.
  • Always follow the product label, statutory conditions of use, buffer zones, stewardship guidance and operator requirements.

How to use the spray calculator

Start by recording the hectares you intend to spray, the sprayer tank you plan to operate and the water rate authorised for each product pairing. Optionally name the sprayer rig, field or crop—these cues flow into summaries you can print or paste into farm software. Layer on one or more products once you understand their label sections (dose volumes or weights per hectare, buffering, drift reduction and equipment restrictions). Rates are intentionally manual: paste in your intended dose expressed as L/ha, ml/ha, kg/ha or g/ha depending on formulation. Packaging size and indicative price unlock pack counts plus two cost views when you truly need budgeting help as well as volume planning.

Spray calculator formulas

  • Area covered per nominal tank: tank size (litres) ÷ water rate (litres/hectare).
  • Total water for the travelling pass: field area × water rate — remember to add in any dedicated nozzle flush or tank rinse strategy separately because this row only tackles the spray delivery volume.
  • Herbicide, fungicide or insecticide fraction per tank: normalised dose per hectare × hectares each tank realistically covers once booms behave evenly across the paddock contour.
  • Whole-field product mass or volume: normalised dose × total hectares irrespective of how many passes you mechanically split loading into.

How to calculate hectares per tank

Picture a nominal 3,000 L nominal fill spraying at 200 L/ha. Dividing litres by water rate predicts 15.0 hectares per brim-full charge because every hectare consumes 200 L carrier. Narrower spraying with lower litre-per-hectare concentrates stretch distance drastically; creeping higher litre rates shrink tank reach and increase mixing frequency. Terrain, overlaps and valve losses still matter operationally—the calculator expresses ideal maths so you tie in field checks.

How to calculate product per tank

Suppose authorised spray partners allow 1 L/ha concentrate and each full carrier volume addresses 15 ha. Multiply 1 × 15 = 15 L per completed tank plus any adjuvant obligations defined elsewhere on the SDS. Matching micro rates (grams or ml) requires minding decimals: the tool internally promotes millilitres to litres and grams to kilograms without you juggling trailing zero mistakes.

How to calculate a part tank

Complete fields rarely finish on perfect multiples of tank litres. Subtract each full nominal tank from total mixed volume; the litres left comprise the fractional pass. Dividing leftover litres by the same water intensity tells you how large the tail area is physically. Multiply that partial area by each product dose to finish without overdosing residues in the cropped headland stripe and without under-dosing sheltered pockets.

Water rate in litres per hectare

Agronomically, water behaves as engineered carrier aligning droplet spectra, deposition and uptake windows. Regulatory guidance often nests minimum/maximum aqueous-phase expectations inside product authorisations alongside crop growth stage limits and environmental buffers. Selecting a litre rate that conflicts with approvals undermines stewardship even if volumetric maths still balances neatly.

Product label rate and legal use

This webpage never substitutes for statutory summaries. Product choice, permissible dose floors and ceilings, number of allowable applications within a cropping window, rotational restrictions after harvest, livestock exclusion intervals, aquatic buffer distances, LERAP categories and stewardship annexes reside only on approvals and SDS packs. Agronomists can interpret nuanced scenarios—but the legal conditions remain anchored to those documents irrespective of calculators.

Multiple products and tank mixes

Multi-product sprays demand compatible formulation chemistries plus safe mixing choreography respecting induction hopper turbulence, dissolution order and sieve screens. Estimate mass or volume of each partner here, yet still cross-check antagonisms, ammonia-driven separations or thickening before you commit concentrates in the yard. Leverage MyAgronomist's Tank Mix Checker when matching partners—not only because of crop safety but due to stewardship recording expectations auditors request.

The Frequently asked questions below expand on hectares per tank loads, fractional volumes, copying results and distinguishing advisory limits from maths-only outputs.

Frequently asked questions

How do I calculate how many hectares a sprayer tank will cover?

Divide the tank volume you fill (litres) by your water rate in litres per hectare. For example a 3,000 L tank at 200 L/ha covers about 15 ha per charge.

How much water do I need to spray a field?

Multiply field area (hectares) by application water rate (L/ha). That yields total litres of diluted spray broth before accounting for rinsing.

How do I calculate product per tank?

Multiply the label or recommended dose per hectare (normalised consistently) by the hectares one charge of water covers — this tool does that arithmetic when you supply tank size and water rate.

How do I calculate a part tank?

Subtract full tank volumes from total water needed; the leftover litres divided by water rate gives the hectares in the partial load, and multiply that area by dose rate for each product.

Can I add multiple products?

Yes. Enter each authorised rate independently. Compatibility, mixing sequence and nozzle choice must still match label and professional tank-mix advice — use MyAgronomist’s tank mix checker alongside this.

Does this calculator tell me what rate to spray?

No. It does not prescribe products or doses. You choose rates yourself from the authorised label or your agronomist; the calculator only converts those rates into litres or kilograms relative to tanks and hectares.

Should I use the label rate?

Yes. Crop protection statutory conditions of use tie legality and efficacy to labelled rates unless a professional directs an alternative that remains compliant. Mistakes exceed label maxima or authorised patterns can be offences.

What if my final part tank is very small?

Very small residuals can mislead flowmeters or leave products poorly suspended. Either adjust field boundaries, nozzle selection and drive speed deliberately, overspray an adjacent permissible area legally, or re-plan mixes — this tool warns when residual water is tiny compared with tank nominal volume.

Can I print a spray job sheet?

Yes. Use “Print spray sheet” to capture the summary including date reminders and disclaimers suited to an office briefing or cab checklist.

Can I use this calculator for liquid and granular products?

Liquids normalize to litres per hectare; solids normalize to kg per hectare. They are summarised separately so you never unknowingly blend incompatible mass totals.

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