Fertilizer Rate Calculator
Soil tests give nutrient needs in pounds of N, P2O5, K2O per acre — but you buy fertilizer by the bag. This converts the recommendation into product pounds and cost.
What does this tool do?
Fertilizer Rate Calculator computes the result directly in your browser — Soil tests give nutrient needs in pounds of N, P2O5, K2O per acre — but you buy fertilizer by the bag. This converts the recommendation into product pounds and cost. Nothing you enter is uploaded or stored.
Formula (Cropaia/NRCS): fertilizer product needed (lb/acre) = nutrient rate (lb/acre) × 100 ÷ % nutrient in the fertilizer. Example: 50 lb N/acre with urea 46-0-0 = 50 × 100 ÷ 46 = 108.7 lb product/acre. Read the grade as N-P2O5-K2O: for phosphorus use the second number, potassium the third. Cost: total pounds ÷ 2000 = tons; tons × price per ton = cost. Caution: follow soil-test recommendations and local nutrient-management rules — over-application wastes money and pollutes water.
FAQ
How do I convert a nutrient rate to product?
Divide the desired pounds of nutrient per acre by the nutrient percentage in the fertilizer (as a decimal), i.e., rate × 100 ÷ grade %. Urea 46% N: 50 lb N ÷ 0.46 = 108.7 lb of urea.
What do the three numbers on fertilizer mean?
They're the guaranteed N-P2O5-K2O percentages: nitrogen, phosphate, and potash. 46-0-0 is straight nitrogen (urea); 12-61-0 is MAP (mostly phosphate). Use the number matching the nutrient your soil test calls for.
How much does fertilizer cost per acre?
In 2026 examples, urea runs roughly $350-$550/ton, so 50 lb of N costs about $40-$65 per acre depending on the N price. Use your actual delivered price.
Figures are editable example defaults for planning, not guarantees. Crop inputs, prices, and moisture handling vary by farm, region, and year — verify with your local extension service and agronomist.