The Fertilizer NPK Application Sizer calculates exact product poundage and bag quantities required to apply targeted nitrogen levels per 1,000 square feet of lawn turf.

### Fertilizer Chemistry & Application Formulas Bagged fertilizers display three numbers representing guaranteed percentages of Nitrogen (N), Available Phosphate ($P_2O_5$), and Soluble Potash ($K_2O$): - **Product Application Rate per 1,000 Square Feet**: $$\text{Pounds per 1{,}000 sq ft} = \frac{\text{Target Nitrogen Rate (lb)}}{\text{Nitrogen Percentage} / 100}$$ - **Total Fertilizer Product Required**: $$\text{Total Pounds} = \left\lceil \left( \frac{\text{Lawn Area (sq ft)}}{1{,}000} \right) \times \text{Pounds per 1{,}000 sq ft} \right\rceil$$ - **Standard 35-lb Bags Needed**: $$\text{Bags Required} = \left\lceil \frac{\text{Total Pounds}}{35} \right\rceil$$

### Worked Calculation Example Treating a 6,000 square foot residential lawn using 24-0-4 fertilizer (24% Nitrogen) targeting 1.0 lb Nitrogen per 1,000 square feet: - **Rate per 1,000 sq ft**: $1.0 / 0.24 \approx 4.17\text{ lbs product / 1,000 sq ft}$ - **Total Lawn Product**: $(6{,}000 / 1{,}000) \times 4.17 = 6 \times 4.17 = 25.02 \implies 26\text{ lbs}$ - **Bag Takeoff**: One standard 35-lb bag provides sufficient coverage for the entire 6,000 sq ft treatment.

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