Calculate lawn fertilizer bags needed per application and per year.
Bags to buy (per year)
Annual plan
Usage Tip
Follow the bag's recommended rate and do not double up; over-fertilizing burns the lawn and runs off into waterways.
annual bags = bags per application × applications
Bags per application round up to whole bags.
How much fertilizer do I need?
Lawn fertilizer is measured by the nitrogen it delivers, not by the bag. The standard target is about 1 lb of nitrogen per 1,000 sq ft per application. How much product that takes depends on the first number in the analysis — a 24-0-6 fertilizer is 24% nitrogen, so it takes about 4 lb of product to deliver 1 lb of nitrogen. This calculator turns your lawn size and fertilizer analysis into pounds of product, the number of bags to buy, and a full-year plan.
Fertilizer per 1,000 square feet
To hit 1 lb of nitrogen per 1,000 sq ft, divide that rate by the nitrogen percentage. For a 5,000 sq ft lawn and a 24-0-6 product: 5 x (1 / 0.24) is about 21 lb of fertilizer per application. Lower-nitrogen products need more bagged weight to deliver the same nitrogen.
Fertilizer coverage chart
Typical bag coverage at normal lawn rates — handy when you are standing in the aisle:
| Bag size | Approx coverage |
|---|---|
| 15 lb | about 5,000 sq ft |
| 25 lb | about 8,000 sq ft |
| 40 lb | about 12,000 sq ft |
| 50 lb | about 15,000 sq ft |
Fertilizer application rates by grass
Different grasses want different amounts of nitrogen over a year. Spread it across several feedings rather than all at once:
| Grass | Annual nitrogen (lb N / 1,000 sq ft) |
|---|---|
| Fescue | 2 to 3 |
| Kentucky bluegrass | 3 to 4 |
| Ryegrass | 2 to 4 |
| Zoysia | 3 to 4 |
| Bermuda | 4 to 5 |
| St. Augustine | 4 to 5 |
Lawn fertilizer schedule
A simple seasonal plan spreads the annual nitrogen across the growing season. Cool-season lawns lean on spring and fall; warm-season lawns feed most in summer.
| Season | Typical feeding |
|---|---|
| Spring | Wake-up feeding as growth starts |
| Summer | Light feeding; avoid stressing in heat |
| Fall | Heaviest feeding for cool-season grass |
| Late fall | Winterizer, high in nitrogen and potassium |
Reading the N-P-K numbers
The three numbers are the percentages of nitrogen, phosphorus and potassium by weight. A 32-0-10 winterizer is 32% nitrogen, no phosphorus and 10% potassium. Nitrogen drives green growth, phosphorus supports roots, and potassium hardens the plant for stress and winter.
Frequently asked questions
How much fertilizer for a 5,000 sq ft lawn?
About 20 lb of a 24-0-6 product per application to deliver 1 lb of nitrogen per 1,000 sq ft. Lower-nitrogen blends need more.
How many pounds of nitrogen per 1,000 sq ft?
About 1 lb per application, and 2 to 5 lb per year total depending on grass type.
How do I read fertilizer numbers?
They are the percent nitrogen, phosphorus and potassium. Divide your target nitrogen by the first number to find how much product to spread.
Can I apply too much fertilizer?
Yes. Over-applying burns the lawn and pollutes runoff. Stick to about 1 lb of nitrogen per 1,000 sq ft per feeding.
When should I fertilize my lawn?
Cool-season grass in spring and fall, warm-season grass through summer. A late-fall winterizer helps cool-season lawns.
What is a winterizer fertilizer?
A late-season feed high in nitrogen and potassium, like 32-0-10, that strengthens roots before dormancy.
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Estimates are for planning. Follow the product label, which is the legal application rate; never exceed about 1 lb of nitrogen per 1,000 sq ft per feeding, water in as directed, and avoid applying before heavy rain to protect waterways.