What this calculator does
Fertilizer application rate works out product needed to hit a target nutrient rate given the label percentage. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
Formulaproduct rate = target rate / (label % / 100); total = product rate × area
The inputs explained
| Field | What to enter |
|---|---|
| Target nutrient rate (lb N/1000 ft²) | A number, measured in lb N/1000 ft². Starts at 1. |
| Nutrient % on label (%) | A number, measured in %. Starts at 20. |
| Area to treat (ft²) | A number, measured in ft². Starts at 5000. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with target nutrient rate
Every other input is held at the calculator’s starting values while target nutrient rate varies. Select any row to load that scenario into the calculator.
How the answer changes with target nutrient rate