Free fertilizer application calculator. Calculate the exact amount of fertilizer needed based on nutrient recommendations, fertilizer analysis, and field size. Includes cost estimation.
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Applying the right amount of fertilizer is critical for crop health, yield optimization, and environmental stewardship. Our calculator helps you determine exactly how much fertilizer product to apply based on your soil test recommendations and the fertilizer's NPK analysis.
Fertilizer products list their nutrient content as N-P-K percentages (e.g., 10-10-10). To meet a specific nutrient recommendation (like 100 lbs N/acre), you need to calculate how much product delivers that nutrient. The formula accounts for the nutrient percentage in the fertilizer.
Product Rate Formula
Product Rate = Nutrient Rate ÷ (Nutrient % ÷ 100)Deliver exactly the nutrients your soil test recommends for maximum yield.
Avoid over-application that wastes money and harms the environment.
Prevent nutrient runoff by applying only what crops can use.
Calculate urea or UAN needs to meet nitrogen recommendations.
Determine DAP or MAP rates for phosphorus-deficient soils.
Use blended products like 10-10-10 for balanced nutrition.
Estimate fertilizer costs before the growing season.
Fertilizer labels show phosphorus as P₂O₅ (phosphate), not elemental P. To convert P₂O₅ to P, multiply by 0.44. Soil tests typically recommend P₂O₅, matching fertilizer labels.