Formula used
How to use this calculator
- Select the calculation mode matching your mixing task.
- Enter final volume, area, plants, or injector details.
- Add the fertilizer label analysis and product density.
- Enter prices when cost estimates are needed.
- Calculate, review warnings, then confirm the product label.
Use actual product density whenever possible. Water-like density assumptions can distort concentrated liquid quantities. Always test small batches before large applications.
Example data
| Example | Inputs | Expected purpose |
|---|---|---|
| Basic dilution | 100 L, ratio 1:100 | Find concentrate and water. |
| Nitrogen target | 150 ppm N, 100 L, 10% N | Find product mass and liquid volume. |
| Injector stock | 1:100 injector, 20 L stock tank | Prepare concentrated stock solution. |
| Area treatment | 500 m², 10 L per 100 m² | Plan total solution and tank loads. |
| Blend check | Two known fertilizer amounts | Estimate combined nutrient ppm. |
Saved calculation history
Frequently asked questions
What does a 1:100 fertilizer ratio mean?
It can mean one part concentrate in one hundred total parts, or one part concentrate added to one hundred water parts. Select the matching interpretation before calculating.
Is ppm the same as mg/L?
For dilute water-based solutions, one ppm is approximately one milligram per litre. Very dense or concentrated solutions may require more exact mass-based methods.
Why does fertilizer density matter?
Nutrient guarantees usually describe mass percentages. Density converts required product mass into a measurable liquid volume.
Can I mix several fertilizers together?
The blend mode totals their declared nutrients. It cannot guarantee chemical compatibility, precipitation safety, or crop tolerance.
How are phosphorus and potassium converted?
The calculator converts P₂O₅ to elemental phosphorus using 0.4364. It converts K₂O to elemental potassium using 0.8301.
Can this replace a soil or water test?
No. Testing identifies existing nutrients, salts, alkalinity, and other factors that determine an appropriate fertilisation programme.
Why can calculated water be approximate?
Some dissolved products change final volume after mixing. Professional formulation may use final-volume make-up rather than simple subtraction.
What injector ratio should I use?
Use the verified ratio from the injector calibration. Nominal settings can differ from actual draw rates.
How should powders be measured?
Measure soluble powders by mass with a suitable scale. Household spoons are unreliable for concentrated products.
What should I do when a warning appears?
Recheck units, density, analysis percentages, and label rates. Reduce the batch size when testing an unfamiliar recipe.
Safety notice
This calculator provides planning estimates, not agronomic prescriptions. Follow product labels, local regulations, crop limits, and personal protective equipment requirements. Never combine incompatible concentrates without a documented compatibility test.