Advanced Soil Fertilizer Calculator (NPK + Ca, Mg, S)
This farmer-friendly tool converts your target nutrients into practical fertilizer recommendations per acre. It accounts for overlaps (e.g., DAP supplies both N and P) and switches to TSP if DAP would oversupply nitrogen. You’ll get outputs in kg/acre and 50-kg bags.
1) Application Basis
Example: 100 kg/acre total fertilizer to be applied. Change as needed.2) Target Nutrients (%)
Phosphorus is labeled as P₂O₅ (oxide form). DAP/TSP supply P₂O₅. Potassium is labeled as K₂O (oxide form). MOP supplies K₂O.3) Optional Secondary Nutrients (%)
Results will appear here
Enter your targets and click calculate.
Fertilizer analysis used:
- Urea: 46% N
- DAP: 18% N, 46% P₂O₅
- TSP: 46% P₂O₅
- MOP (Muriate of Potash): 60% K₂O
- Gypsum: ~23% Ca, 18% S
- Kieserite (MgSO₄·H₂O): ~16% Mg, 13% S
- Elemental Sulfur: 90% S
FAQs
How do I choose the right nutrient targets?
Use your soil test and local extension recommendations. If none are available, start modestly and adjust after observing crop response.
Can I change per-acre to per-hectare?
Yes. Multiply kg/acre by 2.47 to get kg/hectare, or change the Total application per acre to an equivalent per-hectare basis.
What if I prefer SOP instead of MOP?
SOP (0-0-50) supplies K₂O at 50% instead of 60%. Divide your K₂O target (kg) by 0.50 to get SOP kg needed.