Lawn Fertilizer Calculator

Use this fertilizer calculator to determine how much fertilizer is needed to cover your lawn according to recommended rates.  The information needed is lawn area in square feet, the recommended rate of Nitrogen (lbs N/1000 sq ft), and the fertilizer analysis (or grade) of the fertilizer product that you want to use.

To determine how much fertilizer to apply to your lawn

  1. Measure the area of your lawn in square feet.  Measure your lawn with a tape measure or use an online tool such as the Google Area Calculator (link opens in a new window).
  2. Determine the recommended rate of Nitrogen.  Nitrogen recommendations are usually given in lbs/1000 sq. ft. and made for the grass type being grown.  There are some general recommendations in the 'grass types' section of this website.  I also recommend checking with your state's extension service for nitrogen fertilizer rates.  Please contact me if you need help determining an appropriate nitrogen fertilizer rate.  Phosphorus, potassium, and micronutrients recommendations are based on soil tests.
  3. Choose the fertilizer product that you would like to use and look for the fertilizer analysis on the label. The Fertilizer Analysis (N-P-K) is the three numbers on the label and it indicates the percent by weight of nitrogen, phosphate (P2O5), and potash (K2O) in the fertilizer.  This information is required to be on every fertilizer label. 

One way to compare fertilizer products is cost per pound of Nitrogen.  Use this fertilizer calculator to determine the cost per pound of nitrogen in a bag of fertilizer.

Read more about choosing the best lawn fertilizer.

Ferti-Lome Lawn Fertilizer Label

Here's an example of a fertilizer analysis on a Ferti-Lome label.  Ferti-lome is available at DoMyOwn.

Fertilizer Analysis on the front side of a fertilizer labelFertilizer Analysis on the front side of a bag
Fertilizer Analysis found on the back side of the fertilizer bagFertilizer Analysis found on the back side of the fertilizer bag

Calculator Instructions

  1. Enter the size of your lawn (ex 5000 sq ft)
  2. Enter the target rate of Nitrogen (lb N/1000 sq ft) Use decimal not fraction (ex .75 not 3/4)
  3. Enter the Amounts of N - P - K (ex 24 - 0 - 4)
  4. Click the 'Calculate' button

The results will tell you how much fertilizer is needed to cover your lawn, as well as how much phosphate (P) and potash (K) you are applying per 1000 sq ft.  It will also give you the amount of fertilizer needed per acre for treating large sites.

Lawn Fertilizer Calculator

Lawn Fertilizer Calculator

Want to know what your lawn needs and when to apply it?

Let the turfgrass experts at Sunday take care of the technical stuff.

Have you heard about the Sunday Smart Lawn Plan? It's simple, do-it-yourself natural lawn care that's customized to your soil, climate, and lawn.  Delivered to you right when you need it.  You apply the nutrient packets with the included hose-end sprayer...simple, professional results!

Sunday's plant and soil nutrient products are made from food waste, seaweed, and molasses.  The natural additives stimulate plant growth and activate soil life.

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