CONSTRUCTION

Lawn fertilizer calculator

Answers the question: How much lawn fertilizer do I need?

This lawn fertilizer calculator helps you find the right amount of fertilizer to use on your lawn. In addition to the size of the area to be fertilized, we do this calculation using the NPK values of your lawn fertilizer. NPK stands for Nitrogen, Phosphorus, and Potassium. Nitrogen is the governing element for calculating the required lawn fertilizer. You can find the NPK values on the fertilizer bag.

If you select an option that has the same underlying value as another option, both (all) will be marked.
If you select an option that has the same underlying value as another option, both (all) will be marked.

Results

Fertilizer needed: 7.5 kilograms
Fertilizer needed: 16.53 pounds

This NPK calculator should only be used with NPK fertilizers. Do not use this for fertilizers containing calcium nitrate.


Our calculations

At Calculatorian, we are keen to share our knowledge, be transparent and open to feedback. Here are the calculations used to create this calculator. If you find an error or deficiency, contact us and we'll fix it in an instant!

Fertilizer needed was calculated like this:

Step 1

First we need to calculate the variable N. N = Nitrogen.

Step 2

Then we need to calculate the variable kgs. kgs = fertilizer needed if not thinking about growth season.

Step 3

Finally we put it together and calculate it like this:

Fertilizer needed was calculated like this:

Variables used in this formula

n = Nitrogen (N)
p = Phosphorus (P)
k = Potassium (K)
a = Lawn area that shall be fertilized

Depending on your choice when selecting lawn area in square meters or square feet? a constant is applied as the variable at in the formula.

Lawn area in square meters or square feet?at
Square meters1
Square feet10.76391042

Depending on your choice when selecting start of growth season or later? a constant is applied as the variable t in the formula.

Start of growth season or later?t
Start1
Later0.6