Fertilizer Calculator (NPK: How Much Product to Apply)
Enter the bag’s N-P-K numbers, the nitrogen rate and the area.
Your numbers
Your results
Product to apply (lb)
Product to apply (lb)
—
Per 1,000 sq ft (lb)
—
Product to apply (kg)
—
Phosphate applied (lb P₂O₅)
—
Potash applied (lb K₂O)
—
Fertilizer Calculator (NPK: How Much Product to Apply) by TheCalcTools
How the Fertilizer Calculator (NPK: How Much Product to Apply) works
The three numbers on a fertilizer bag are the percentages by weight of nitrogen (N), phosphate (P₂O₅) and potash (K₂O). To apply 1 lb of nitrogen, spread 1 ÷ (N% ÷ 100) lb of product.
Lawn recommendations are usually given as pounds of nitrogen per 1,000 sq ft per application; base phosphate and potash on a soil test.
The formula
Product (lb) = N rate ÷ (N% ÷ 100) × area ÷ 1,000
Worked example
Using the default values shown in the calculator:
| Nitrogen % (first number) | 24 |
|---|---|
| Phosphate % (second number) | 0 |
| Potash % (third number) | 6 |
| Nitrogen to apply (lb per 1,000 sq ft) | 1 |
| Area (sq ft) | 5000 |
- 24-0-6 at 1 lb N per 1,000 sq ft: 4.17 lb of product per 1,000 sq ft.
- For 5,000 sq ft spread 20.83 lb.
Result:
| Product to apply (lb) | 20.83 |
|---|---|
| Per 1,000 sq ft (lb) | 4.17 |
| Product to apply (kg) | 9.45 |
| Phosphate applied (lb P₂O₅) | 0.00 |
| Potash applied (lb K₂O) | 1.25 |
Frequently asked questions
How much 24-0-6 for 1 lb of N per 1,000 sq ft?
About 4.17 lb of product per 1,000 sq ft.
Sources and further reading
Related calculators
More in Hobbies: Photo, Music & Garden · All calculators
This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.