Fertilizer NPK Rate Calculator
Turn a fertilizer bag label into an exact amount to spread instead of guessing. Enter the three NPK numbers from the bag, which are the percent nitrogen, phosphate and potash by weight, then set your target rate of actual nitrogen in pounds per thousand square feet and the area you are feeding. The calculator divides your nitrogen goal by the nitrogen percent to find the pounds of product to apply, then shows how much phosphate and potash that same amount delivers. A common lawn and garden rate is about one pound of nitrogen per thousand square feet per feeding. Knowing the actual nutrient rate prevents burning plants and wasting product. Everything is calculated instantly in your browser with no signup.
How to use Fertilizer NPK Rate Calculator
- Enter the N, P and K percentages from the bag.
- Enter your target pounds of nitrogen per 1000 square feet.
- Enter the area you are treating.
- Read the pounds of product to apply and the P and K it supplies.
Frequently asked questions
How does it turn an NPK analysis into pounds of product?
It divides your target nitrogen per 1000 square feet by the nitrogen percent on the bag, then scales by your area to give the pounds of product to spread.
Why base the rate on nitrogen?
Nitrogen drives most growth and is the number most fertilizer programs target, so the tool sets the application to hit your desired nitrogen, then reports the P and K that follow.
What are the three numbers on a fertilizer bag?
The bag analysis lists the percent of nitrogen, phosphorus and potassium by weight, and the tool uses those percentages to work out how much of each you apply.
What is Fertilizer NPK Rate Calculator?
Turn a fertilizer bag label into an exact amount to spread instead of guessing. Enter the three NPK numbers from the bag, which are the percent nitrogen, phosphate and potash by weight, then set your target rate of actual nitrogen in pounds per thousand square feet and the area you are feeding.
Is Fertilizer NPK Rate Calculator free to use?
Yes. Fertilizer NPK Rate Calculator is completely free, with no sign-up and no usage limits.
Does Fertilizer NPK Rate Calculator work in a web browser?
Yes. Fertilizer NPK Rate Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Fertilizer NPK Rate Calculator?
Yes. Fertilizer NPK Rate Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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