Fertilizer rate calculator (NPK)
PROPounds of fertilizer to apply your target N rate.
Short answer: lb fertilizer per 1,000 sq ft = target N ÷ (%N ÷ 100). 21-0-0 to deliver 1 lb N/K: 1 ÷ 0.21 = 4.76 lb per 1,000 sq ft. Enter your measurements above and the fertilizer rate calculator (npk) returns the quantity, unit conversions and an estimated cost instantly, in imperial or metric — no sign-up needed.
What do you need to measure?
What is the answer?
Fertilizer per 1,000 sq ft
4.76 lb
Total fertilizer
4.8 lb
50 lb bags
1
How does the fertilizer rate calculator (npk) work?
lb fertilizer per 1,000 sq ft = target N ÷ (%N ÷ 100).
What does a worked example look like?
21-0-0 to deliver 1 lb N/K: 1 ÷ 0.21 = 4.76 lb per 1,000 sq ft.
What do people ask most?
›Typical N target?
0.5–1.0 lb N per 1,000 sq ft per feeding on lawns.
Which garden calculator should you use next?
Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.