Fertilizer Calculator
Lawn & Garden · Updated July 2026
Enter your lawn area and application rate to find how many pounds of fertilizer to apply for even, healthy coverage.
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Estimates only. Add extra for waste and confirm with your supplier.
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How much fertilizer do I need?
Multiply your lawn area (in thousands of sq ft) by the application rate on the bag, usually given in pounds per 1,000 sq ft.
Reading the application rate
Fertilizer bags list a rate in pounds per 1,000 sq ft. Multiply your lawn area (in thousands of sq ft) by that rate to find how much to apply, and split it into two passes for even coverage.
Understanding N-P-K
The three numbers on the bag are nitrogen, phosphorus, and potassium by percentage. Nitrogen drives green growth; a soil test tells you what your lawn actually needs so you don't over-apply and cause runoff.
How to use this calculator
- 1Measure your lawn area in square feet.
- 2Enter the rate from the fertilizer bag.
- 3Read the pounds needed.
Frequently asked questions
How do I read a fertilizer rate?
Bags list an application rate per 1,000 sq ft. Match it to your lawn size to avoid over- or under-applying.
How much fertilizer do I need?
Multiply your lawn area (in thousands of sq ft) by the rate on the bag (lb per 1,000 sq ft).
What do the numbers on fertilizer mean?
They're the percentages of nitrogen, phosphorus, and potassium (N-P-K) in the bag.
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