How much fertilizer per 1000 square feet
Wondering how much fertilizer per 1000 square feet your lawn or garden needs? Enter your area, your target nitrogen rate, and the N-P-K grade on your fertilizer bag, and this free fertilizer rate calculator tells you exactly how many pounds of product to spread, how many bags to buy, and how much phosphorus and potassium you'll be applying along the way. Results update instantly as you type.
Enter your numbers
Your results
| Breakdown | Value |
|---|---|
| Product per 1,000 sq ft | — |
| Phosphorus (P) applied | — |
| Potassium (K) applied | — |
| Exact bags (decimal) | — |
Guideline only: 1 lb of nitrogen per 1,000 sq ft per application is a common recommendation, not a prescription. A soil test is the best way to confirm what your lawn or garden actually needs — many soils already have enough phosphorus.
How to use this calculator
Start with your area in square feet — measure only the ground you plan to fertilize, not the whole property. Then enter your target nitrogen rate: 1.0 lb of nitrogen per 1,000 sq ft per application is the standard guideline for lawns, while vegetable gardens and flower beds typically need 0.5–1.0.
Next, read the N-P-K grade off your fertilizer bag (the three hyphenated numbers, like 24-0-6 or 10-10-10) and enter the three percentages. A higher nitrogen percentage means less total product per pound of nitrogen — the calculator handles the conversion either way.
Finally, enter your bag weight so the results can tell you how many bags to buy (rounded up to whole bags). The product to spread figure is the headline number: weigh or measure it out, spread it evenly, and water it in unless the bag instructions say otherwise.
How it works
The calculation is built on one rule: nitrogen is the nutrient lawns need most of, and fertilizer rates are set by nitrogen. First, the tool converts your area to thousands of square feet (areaK = area ÷ 1,000), then multiplies by your target rate: total nitrogen = areaK × target rate. For a 5,000 sq ft lawn at 1.0 lb N per 1,000 sq ft, that's 5 × 1.0 = 5 lb of nitrogen.
The N-P-K grade tells you what fraction of the product is nitrogen, so product needed = total nitrogen ÷ (N% ÷ 100). With a 24-0-6 fertilizer, that's 5 ÷ 0.24 = 20.83 lb of product — less than half a 50 lb bag. The same formula explains why a 10-10-10 needs 5 ÷ 0.10 = 50 lb for the same 5 lb of nitrogen.
The phosphorus and potassium rows simply multiply the product weight by the P and K percentages: the 20.83 lb of 24-0-6 applies 0 lb of phosphorus and 1.25 lb of potassium. Bags are rounded up because you can't buy a fraction of a bag. These rates are general guidelines — soil type, grass species, season, and local rules (some states restrict phosphorus) all matter, so get a soil test for a prescription tailored to your yard.
Frequently asked questions
What do the three numbers on a fertilizer bag mean?
They are the N-P-K grade: the percentage by weight of nitrogen (N), phosphate (P2O5), and potash (K2O), in that order. So a 24-0-6 bag is 24% nitrogen, 0% phosphate, and 6% potash — every 100 lb of it carries 24 lb of nitrogen and 6 lb of potash. Higher nitrogen grades mean less total product per pound of nitrogen, which is exactly what this calculator works out for you.
How much 10-10-10 do I need for 1,000 square feet at 1 lb of nitrogen?
10 lb of product. With a 10% nitrogen grade, each pound of nitrogen requires 10 lb of product (1 ÷ 0.10), and that 10 lb also applies 1 lb of phosphate and 1 lb of potash. For a 5,000 sq ft lawn at the same rate, you'd need 50 lb — one standard bag. Enter your own grade above to get the exact number for your lawn.
Is it okay to apply more fertilizer than the recommended rate?
No — more is not better. Excess nitrogen can burn your grass, leaving brown or yellow patches, and excess phosphorus washes off into waterways. Most turf guidelines cap a single application at about 1 lb of nitrogen per 1,000 square feet. If your lawn is struggling, a soil test will tell you whether the problem is nutrients, pH, watering, or something else.
When is the best time to fertilize my lawn?
Cool-season grasses (fescue, bluegrass, rye) do best with fall feedings — early September and late October or early November in most climates — plus a light spring application. Warm-season grasses (bermuda, zoysia, St. Augustine) should be fertilized after they green up in late spring and again in summer. Avoid fertilizing dormant or heat-stressed grass, and don't spread fertilizer before heavy rain.
Do I need a soil test before fertilizing?
A soil test is the only way to know exactly what your soil needs, and it usually pays for itself. Many soils already have plenty of phosphorus, so a test can save you from buying a more expensive balanced fertilizer when a nitrogen-only product would do. Contact your local cooperative extension office — tests are typically inexpensive and include pH and nutrient recommendations.