Lawn Fertilizer Calculator
Work out how many bags of lawn fertilizer a yard needs, using a standard 1 lb of nitrogen per 1,000 sq ft.
Calculator
| Nitrogen at 1 lb / 1,000 sq ft | 5.0 lb |
|---|---|
| Product if the bag is 20% nitrogen | 25.0 lb |
How it is calculated
5,000 sq ft ÷ 1,000 × 1 lb of nitrogen = 5.0 lb N. With a 20% nitrogen fertilizer that is 25.0 lb of product; a bag covering 5,000 sq ft means 1 bag(s).
About this calculator
Fertilizer labels list three numbers (N-P-K). For turf, nitrogen is the one most people plan around, and a common single application is about 1 pound of nitrogen per 1,000 square feet. This calculator turns your lawn size into pounds of nitrogen and into bags.
To convert nitrogen into product, divide by the nitrogen percentage on the bag: a 20% nitrogen fertilizer takes 5 pounds of product for 1 pound of nitrogen. Always follow the rate and timing on the label of the fertilizer you buy.
Worked examples
| Project | Bags covering 5,000 sq ft each | Rough cost |
|---|---|---|
| 1,000 sq ft of lawn | 1 bags | $15.00 – $45.00 |
| 5,000 sq ft of lawn | 1 bags | $15.00 – $45.00 |
| 10,000 sq ft of lawn | 2 bags | $30.00 – $90.00 |
| 21,780 sq ft of lawn | 5 bags | $75.00 – $225 |
Buying notes
- Check the coverage printed on the bag; sizes and rates differ between products.
- Apply in even passes and sweep granules off hard surfaces so they do not wash into drains.
- Avoid applying right before heavy rain or when the lawn is stressed by heat or drought.
Quick answers by size
Click a size for the exact quantity and cost.
How to measure and use this calculator
- Measure your lawn in square feet.
- Read the nitrogen needed and the bag count for 5,000 sq ft bags.
- Check the bag label for its own coverage and rate, which takes priority.
- Apply evenly and water it in as directed.
Common mistakes
- Overlapping passes, which burns the grass.
- Applying before heavy rain, which washes it away.
- Ignoring the label's temperature and season advice.
Tips
- Read the label: the printed coverage and rate for your product always overrides these defaults.
- Apply in even passes and sweep stray granules off hard surfaces.
- Most turf grasses are fed at about 1 lb of nitrogen per 1,000 sq ft per application.
Frequently asked questions
How much fertilizer do I need for 5,000 square feet?
About 5 lb of actual nitrogen, which is a single 5,000 sq ft bag of typical lawn fertilizer.
How do I work out pounds of product from the nitrogen percentage?
Divide the pounds of nitrogen you want by the percentage as a decimal. For 1 lb of nitrogen with a 20% fertilizer, 1 ÷ 0.20 = 5 lb of product.
How often should I fertilize a lawn?
It depends on the grass type and the product. Many lawns are fed a few times a year; follow the schedule that suits your grass and region.