Lawn Fertilizer Calculator

Estimate how much fertilizer product you need per application and per year. Compare annual costs across granular and organic formulas based on nitrogen content.

Lawn Area (sq ft)

N Rate (lbs N / 1,000 sq ft)

Applications / Year

Bag Pricing (edit to match local rates)

10-10-10 / 40 lb bag ($)

20-5-10 / 40 lb bag ($)

Organic 5-3-4 / 50 lb bag ($)

Product per Application

50.0 lbs

2 × 40 lb bag(s) of 10-10-10

Bags per Year

8 bags

4 applications × 2 bags

Annual Cost

$176.00

$44.00 per application

Selected: Granular 10-10-10

N per application: 5.00 lbs actual N

N content: 10%

Product per app: 50.0 lbs

Bag size: 40 lbs

Purchase Option	Quantity	Est. Cost
Granular 10-10-10 (40 lb bag)	8 bags/yr	$176.00
Granular 20-5-10 (40 lb bag)Best value	4 bags/yr	$128.00
Organic 5-3-4 (50 lb bag)	8 bags/yr	$304.00

Best annual value: Granular 20-5-10 at $128.00/yearThe 20-5-10 formula delivers more nitrogen per bag, meaning fewer bags per application and lower overall cost. This is ideal for established lawns that primarily need nitrogen for green-up and growth.

Consider a soil test firstFor lawns over 3,000 sq ft, a soil test ($15–$30 through your local extension office) can reveal exactly which nutrients your lawn needs. You may be able to skip phosphorus and potassium entirely, saving money and reducing environmental runoff.

This is an estimate based on standard fertilizer analysis. Actual needs vary by grass type, soil conditions, climate, and product formulation. Always follow the manufacturer's label rates and local regulations regarding fertilizer application.