Fertilizer Calculator


Estimate Nitrogen Needs for Your Vegetable Garden

This website takes 3 types of data inputs and converts them into an estimate of how much nitrogen-based fertilizer is needed.

Input 1: Nitrogen per Acre

This calculator asks for the nitrogen needs for a crop planted in an acre because this value can often be found at the website
of a county extension office or the land grant university in your state.

Input 2: Length and Width of Your Plot

Input 3: Percentage of Nitrogen in your Fertilizer

Fertilizer purchased in a garden store will have a 3 number code on it. An example would be “12-3-7”. This means the contents of the fertilizer package have 12 percent nitrogen,
3 percent phosphorus, and 7 percent potassium. These are the three primary nutrients a plant will need. Enter the first of these numbers in the next field.


Area of plot (sq ft):

Nitrogen (oz) per sq. ft.:

Nitrogen (oz) per plot:

Amount of fertilizer needed for your vegetable garden: