Fertilizer Cost Calculator

The Fertilizer Cost Calculator compares up to 5 fertilizer products by cost per pound of nitrogen, phosphorus, or potassium. SVG cost comparison chart and nutrient application bars highlight the best value — features an AI chatbot cannot replicate. Free, no sign-up required.

Comparison Presets

Fertilizer Products

N %

P %

K %

Bag Weight (lbs)

Bag Price ($)

N %

P %

K %

Bag Weight (lbs)

Bag Price ($)

Target Application

Target Nutrient

Target Amount (lbs / 1,000 sq ft)

Area Size (sq ft)

Unit System

Cost Comparison

Savings (best vs worst)

$28.00

Product	Grade	Cost / lb Nutrient	Bags Needed	Total Cost
	10-10-10	$4.75	2	$37.98
	32-0-4	$8.18	2	$65.98

Total Cost Comparison

Nutrient Applied per Product

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What is a Fertilizer Cost Calculator?

A fertilizer cost calculator compares multiple fertilizer products by calculating the cost per pound of the target nutrient (nitrogen, phosphorus, or potassium). A bag of 46-0-0 urea at $29 delivers nitrogen at $1.26/lb, while a bag of 10-10-10 at $19 delivers nitrogen at $4.75/lb. The cheapest bag is not always the best value — this calculator finds the true cost per unit of nutrient to help you make informed purchasing decisions.

How to Use This Calculator

Select a preset comparison or add your own fertilizer products
Enter each product's N-P-K grade, bag weight, and bag price
Select the target nutrient you are optimizing for (nitrogen, phosphorus, or potassium)
Enter the target application rate and your area size
Compare the total cost, bags needed, and cost per pound of nutrient
The best value product is highlighted with a badge and savings displayed

Frequently Asked Questions

How do I calculate cost per pound of nitrogen?

Divide the bag price by the pounds of nitrogen per bag. For a 50 lb bag of 46-0-0 urea at $29: nitrogen per bag = 50 × 0.46 = 23 lbs. Cost per lb N = $29 ÷ 23 = $1.26/lb. Compare this across products to find the best value.

Is the cheapest fertilizer always the best value?

No. A $15 bag of 5-5-5 contains much less nutrient per bag than a $30 bag of 46-0-0. The cost per pound of actual nitrogen in the cheap bag may be 3–4 times higher. Always compare cost per unit of nutrient, not cost per bag.

How much nitrogen does a lawn need per year?

Most lawns need 2–4 lbs of nitrogen per 1,000 sq ft per year, split into 2–4 applications. Cool-season grasses (fescue, bluegrass) prefer fall applications. Warm-season grasses (Bermuda, Zoysia) need summer applications. Over-fertilizing wastes money and causes runoff.

Why does the same fertilizer cost different amounts at different stores?

Pricing varies due to brand premium, bag size, formulation (slow-release coating adds cost), and retail markup. Generic or agricultural-grade fertilizers are typically 40–60% cheaper per pound of nutrient than branded consumer products with the same N-P-K analysis.