Fertilizer Rate Calculator

Free fertilizer rate calculator. Enter your fertilizer's N–P–K and your target lbs of nitrogen per 1,000 sq ft — get the exact bag rate for any lawn size.

Frequently asked questions

How do I convert N–P–K to pounds of fertilizer per 1,000 sq ft?

Divide your target pounds of nitrogen per 1,000 sq ft by the nitrogen percentage (the first N–P–K number, as a decimal). To put down 1 lb of N with a 24-0-6 product: 1 ÷ 0.24 ≈ 4.2 lbs of product per 1,000 sq ft.

How much nitrogen does a lawn need?

Most cool-season lawns want 0.5–1 lb of nitrogen per 1,000 sq ft per application and 2–4 lbs per year total. Warm-season grasses and your specific goals shift that range, so confirm with the product label and local guidance.

What do the three N–P–K numbers mean?

They're the percentages by weight of nitrogen (N), phosphorus (P), and potassium (K). A 24-0-6 bag is 24% nitrogen, 0% phosphorus, and 6% potassium; the rest is filler and carrier.

Can I apply too much fertilizer?

Yes — over-applying nitrogen can burn the lawn, push weak surge growth, and run off into waterways. Always stay within the product label's maximum single-application and annual rates.