The calculation, without hidden assumptions
Fertilizer labels state nutrient percentages, while lawn programs often express a target as pounds of actual nitrogen per 1,000 square feet. This calculator performs that conversion only; the target rate remains an explicit user input.
How to use this calculator
Measure the treated area.
Enter the nitrogen target from your soil test, label or local plan.
Enter the first number of the fertilizer analysis as N%, plus package weight, to get product pounds and bags.
Where people use it
- •Translating soil-test targets
- •Comparing fertilizer analyses
- •Whole-bag purchasing
Worked example
A 5,000 ft² lawn at a chosen 0.5 lb N/1,000 ft² target needs 2.5 lb actual N; a 20% N product requires 12.5 lb of product.
What the result does not assume
- •This is arithmetic, not fertilizer advice. Follow labels and nutrient regulations.
- •Phosphorus, potassium, micronutrients and spreader calibration are separate questions.
Frequently asked questions
What does the first fertilizer number mean?+
In an N-P-K analysis, the first number is the percentage by weight of nitrogen.
Does this tell me how much nitrogen my lawn should receive?+
No. You enter the chosen target; the calculator converts it to product weight.
Does this tell me how much nitrogen my lawn needs?+
No. It converts an entered nitrogen target into product weight. Soil tests, product labels and local nutrient rules should determine the target.
Semantic next steps
Continue the calculation
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