Lawn Fertilizer Calculator
Fertilizer rates are set by actual nitrogen, not bag weight. Enter the first number on your fertilizer bag (the N), your target rate and your lawn size to get the exact pounds of product to spread.
Lawn Fertilizer Calculator
Why use the Lawn Fertilizer Calculator
Fertilizer is dosed by actual nitrogen, not bag weight. This converts it so you feed the lawn without burning it.
How to get your numbers
- Lawn area.
- The first N-P-K number on the bag (the nitrogen %).
- Target: no more than 1 lb of actual N per 1,000 sq ft per feeding.
Recommended for this job
How to use it
- Enter your lawn area.
- Enter the first number from the fertilizer bag’s N-P-K (the nitrogen %).
- Set your target — never exceed 1 lb of actual N per 1,000 sq ft at once.
Frequently asked questions
How much fertilizer do I need?
Pounds of product = (target lb N ÷ (N% ÷ 100)) × (area ÷ 1,000). A 24-0-4 bag at 1 lb N covers 1,000 sq ft with about 4.2 lbs.
What do the fertilizer numbers mean?
They are the percentages of Nitrogen, Phosphorus and Potassium (N-P-K) by weight. Nitrogen drives green, leafy growth.
Can I apply too much fertilizer?
Yes — more than 1 lb of actual nitrogen per 1,000 sq ft in one go can burn the lawn. Split heavy feeding into multiple applications.
How much nitrogen per 1,000 square feet?
A typical single application is about 0.5–1 lb of actual nitrogen per 1,000 sq ft — never more than 1 lb at once.
When should I fertilize my lawn?
During active growth — early fall and spring for cool-season grasses; late spring through summer for warm-season grasses.
How often should I fertilize?
Roughly every 6–8 weeks during the growing season, or follow a program of 3–4 well-spaced feedings a year.
Granular or liquid fertilizer?
Granular is easy to spread and often slow-release for even feeding; liquid greens up fast but needs more frequent application.
What is slow-release fertilizer?
It releases nitrogen gradually over weeks, giving steadier growth and less burn risk than fast-release (water-soluble) forms.
