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Landscaping & YardFertilizer Calculator — How Much Fertilizer Do I Need?
Enter your lawn size to estimate the pounds of granular fertilizer for one application, based on a typical spreader rate. Always follow your product’s label rate.
How this calculator works
We multiply length × width for area and apply a common rate of about 4.5 lbs of product per 1,000 sq ft. Your bag’s label rate is the one to trust — it’s set to deliver the right amount of nitrogen.
What changes how much you need
- Product rates differ a lot — the label’s "lbs per 1,000 sq ft" always beats a generic estimate.
- Most lawns want about 1 lb of nitrogen per 1,000 sq ft per feeding.
- Apply in two crosswise passes at half rate each for even coverage.
- Don’t fertilize right before heavy rain — it washes off and pollutes waterways.
Fertilizer needed by lawn size (one application)
At a typical 4.5 lbs of product per 1,000 sq ft — about 1 lb of nitrogen from a 22% N fertilizer. Your bag’s label rate comes first.
| Lawn size | Area | Fertilizer |
|---|---|---|
| Small yard | 1,000 sq ft | 4.5 lbs |
| Townhouse lawn | 2,500 sq ft | 11.3 lbs |
| Average lawn | 5,000 sq ft | 22.5 lbs |
| Large lawn | 10,000 sq ft | 45 lbs |
| Quarter acre | 10,890 sq ft | 49 lbs |
| Half acre | 21,780 sq ft | 98 lbs |
| One acre | 43,560 sq ft | 196 lbs |
Product needed for 1 lb of nitrogen per 1,000 sq ft
Pounds of product = 1 ÷ the first N-P-K number as a decimal.
| Nitrogen (first number) | Example bag | Lbs per 1,000 sq ft |
|---|---|---|
| 10% | 10-10-10 | 10 lbs |
| 16% | 16-4-8 | 6.3 lbs |
| 20% | 20-5-10 | 5 lbs |
| 24% | 24-0-6 | 4.2 lbs |
| 32% | 32-0-4 | 3.1 lbs |
| 46% | 46-0-0 (urea) | 2.2 lbs |
Frequently asked questions
How much fertilizer per 1,000 square feet?
It depends on the analysis, but a common application is about 4–5 lbs of product (≈1 lb of nitrogen) per 1,000 sq ft. Follow the bag.
Why split it into two passes?
Half the rate in each of two crosswise passes evens out coverage and avoids the stripes a single pass leaves.
Can I use too much fertilizer?
Yes — over-applying burns the lawn and runs off into storm drains. Stick to the label rate.
How much fertilizer do I need for 5,000 square feet?
About 22.5 lbs of a typical product at 4.5 lbs per 1,000 sq ft. To hit exactly 1 lb of nitrogen, divide 5 by the nitrogen percentage — with a 24-0-6 fertilizer that’s 5 ÷ 0.24 ≈ 21 lbs. Bags are labeled by the square feet they cover, so a bag rated for 5,000 sq ft is one application whatever it weighs.
How do I calculate fertilizer from the N-P-K numbers?
Divide the nitrogen you want per 1,000 sq ft by the first number as a decimal. For 1 lb of nitrogen with a 20-5-10 fertilizer, that’s 1 ÷ 0.20 = 5 lbs of product per 1,000 sq ft; with 46-0-0 urea it’s about 2.2 lbs. Multiply by your lawn area in thousands of square feet.
How much fertilizer do I need for an acre?
An acre is 43,560 sq ft, so at 4.5 lbs per 1,000 sq ft it takes about 196 lbs of product per application. For 1 lb of nitrogen per 1,000 sq ft you need 43.6 lbs of actual nitrogen — about 182 lbs of a 24% product, or 95 lbs of urea.
How often should I fertilize my lawn?
It depends on the grass. Cool-season lawns (fescue, bluegrass, ryegrass) get most of their feeding in fall, typically 2–4 applications a year. Warm-season lawns (Bermuda, zoysia, St. Augustine) are fed from late spring through summer while actively growing. Your state extension service publishes a calendar for your region.