Fertilizer Calculator

Find the pounds of lawn fertilizer to hit a nitrogen target.

Inputs
ft ×
ft
%
Results update as you type — no submit
ResultsLIVE
Fertilizer to buy
19.2 lb
26% N product
Nitrogen applied
5 lb
at 1 lb N/1000 ft²
Nitrogen applied5 lb
Also equals8.7 kg ≈ 19.2 lb
Formula
N needed = 5000 sq ft × 1 lb N/1000 ft² = 5 lb N
product = 5 lb ÷ 26% = 19.2 lb
Diagram — lawn planNTS
100′ 0″50′ 0″RATE: 1 lb N/1000 ft²LAWN PLAN · NITROGEN RATE
MeasureShedmeasureshed.com/calculator/fertilizer-calculator
Fertilizer — material listUNITS: FT · SCALE: NTS
Inputs
Lawn size100 × 50 ft
Nitrogen rate1 lb N/1000 ft²
Product % N26%
Results
Fertilizer to buy19.2 lb
Nitrogen applied5 lb N
Area5000 sq ft
Lawn planNTS
100′ 0″50′ 0″RATE: 1 lb N/1000 ft²LAWN PLAN · NITROGEN RATE
Shopping list
☐ 19.2 lb of 26% nitrogen fertilizer
Formula
N needed = 5000 sq ft × 1 lb N/1000 ft² = 5 lb N
product = 5 lb ÷ 26% = 19.2 lb
Follow the product label — never exceed 1 lb N / 1,000 sq ft per feedingSHEET 1 OF 1
How it works

Lawns are fed by nitrogen, and fertilizer is dosed by a nitrogen target: a set number of pounds of actual nitrogen per thousand square feet. The bag tells you the percent nitrogen — the first number of the N-P-K analysis — so the product you buy is the nitrogen you need divided by that percentage.

The calculator multiplies the lawn area by your nitrogen rate to get the pounds of nitrogen required, then divides by the bag's percent nitrogen to get the pounds of product. A twenty-six-percent bag delivers a quarter of its weight as nitrogen, so it takes almost four pounds of product for every pound of nitrogen.

Cooperative-extension guidance caps a single feeding at about one pound of nitrogen per thousand square feet — more than that can burn the lawn and run off into waterways. Stay at or below that ceiling, split the season into several light feedings, and always follow the rate printed on the bag.

Worked example
Lawn 100 ft × 50 ft · 1 lb N/1,000 sq ft · 26-0-3 bag (26% N)
nitrogen = 5,000 ÷ 1,000 × 1 = 5 lb N
product = 5 lb N ÷ 0.26 = 19.2 lb of fertilizer
Questions from the lawn
It depends on the bag's nitrogen percent. To apply 1 lb of nitrogen per 1,000 sq ft with a 26% product, you spread about 3.8 lb of product per 1,000 sq ft — roughly 19 lb for a 5,000 sq ft lawn.
Follow the product label — never exceed 1 lb N / 1,000 sq ft per feeding
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