NPK Calculator
Enter Nitrogen (N), Phosphorus (P₂O₅), and Potassium (K₂O) requirements for your crop and area. Get exact quantities of Urea, DAP, MOP, SSP, and NPK complex fertilizers — with cost comparison across 4 combinations.
4 Fertilizer Combinations
DAP + Urea + MOP
Standard recommendation using DAP for phosphorus. Most widely used combination across India.
| Fertilizer | per ha | Total | Cost |
|---|---|---|---|
| DAP | 130.4 kg | 130.4 kg | ₹3,522 |
| Urea | 209.8 kg | 209.8 kg | ₹1,364 |
| MOP | 66.7 kg | 66.7 kg | ₹1,133 |
| Total | 406.9 kg | 406.9 kg | ₹6,019 |
SSP + Urea + MOP
SSP also supplies 11% sulphur and 19% calcium. Ideal for oilseeds, pulses, and sulphur-deficient soils.
| Fertilizer | per ha | Total | Cost |
|---|---|---|---|
| SSP | 375.0 kg | 375.0 kg | ₹2,625 |
| Urea | 260.9 kg | 260.9 kg | ₹1,696 |
| MOP | 66.7 kg | 66.7 kg | ₹1,133 |
| Total | 702.5 kg | 702.5 kg | ₹5,454 |
10-26-26 Complex + Urea
Single complex fertilizer for basal application; reduces number of bags and labour.
| Fertilizer | per ha | Total | Cost |
|---|---|---|---|
| 10-26-26 | 153.8 kg | 153.8 kg | ₹4,308 |
| Urea | 227.4 kg | 227.4 kg | ₹1,478 |
| SSP | 125.0 kg | 125.0 kg | ₹875 |
| Total | 506.3 kg | 506.3 kg | ₹6,661 |
17-17-17 + Top-dress Urea
Balanced complex fertilizer. Good where N, P, K deficiencies are equal.
| Fertilizer | per ha | Total | Cost |
|---|---|---|---|
| 17-17-17 | 235.3 kg | 235.3 kg | ₹5,882 |
| Urea | 173.9 kg | 173.9 kg | ₹1,130 |
| SSP | 125.0 kg | 125.0 kg | ₹875 |
| Total | 534.2 kg | 534.2 kg | ₹7,888 |
Cost Comparison
NPK Calculation Formula
The formula to convert nutrient requirements into fertilizer quantities:
Frequently Asked Questions
What is an NPK calculator?
An NPK calculator converts nutrient requirements (how many kg of Nitrogen, Phosphorus, and Potassium you need per hectare or acre) into the actual fertilizer quantities to purchase and apply. For example, a requirement of 120-60-40 N-P-K translates to: Urea (46% N) = 261 kg/ha, DAP (46% P₂O₅) = 130 kg/ha, MOP (60% K₂O) = 67 kg/ha.
How do I calculate NPK fertilizer doses?
NPK calculation formula: N fertilizer (kg/ha) = N required ÷ N%. P fertilizer (kg/ha) = P₂O₅ required ÷ P%. K fertilizer (kg/ha) = K₂O required ÷ K%. For DAP route: DAP = P/0.46; then remaining N from Urea = (N total – DAP qty × 0.18)/0.46; MOP = K/0.60.
What does 14-14-14 NPK mean?
14-14-14 NPK fertilizer contains 14% Nitrogen, 14% Phosphorus (as P₂O₅), and 14% Potassium (as K₂O) by weight. A 50 kg bag contains 7 kg N + 7 kg P₂O₅ + 7 kg K₂O = 21 kg total nutrients (the rest is carrier/filler). It is a balanced complex fertilizer suitable for mixed crops.
What is the best NPK ratio for crops?
The optimal NPK ratio varies by crop: Rice = 120:60:40 (3:1.5:1), Wheat = 120:60:40 (3:1.5:1), Maize = 150:75:50 (3:1.5:1), Sugarcane = 250:100:120 (2.5:1:1.2), Potato = 180:100:120 (1.8:1:1.2). Legumes (soybean, chickpea) need low N since they fix nitrogen from the air.
How to calculate NPK for 1 acre of land?
1 acre = 0.4047 hectares. Multiply your kg/ha NPK requirement by 0.4047. Example: Rice needs 120 kg N/ha × 0.4047 = 48.6 kg N per acre. Urea needed = 48.6/0.46 = 105.6 kg Urea per acre. DAP = 60 × 0.4047 / 0.46 = 52.7 kg per acre. MOP = 40 × 0.4047 / 0.60 = 27 kg per acre. Use the calculator above for instant results.
Is NPK in kg/ha or kg/acre?
Most crop science publications and government recommendations (ICAR, state agriculture departments) publish NPK requirements in kg per hectare (kg/ha). The calculator accepts kg/ha by default but you can switch to kg/acre in the Rate Unit dropdown. The area can be entered in any unit — the calculator handles all conversions.