NPK Fertilizer Dose Calculator

NPK fertilizer dose per acre for wheat and rice — set N, P and K rates for your field. Use the free NPK Fertilizer Dose Calculator below — enter your values and get instant results, right in your browser. Total nutrient (kg) = field acres × rate per acre, computed separately for N, P and K.

How to use the NPK Fertilizer Dose Calculator

Fertilizer advice comes as N-P-K kilos per acre, but bags are bought per field — and mixing the two up is how nutrients get wasted and money burns. This NPK fertilizer dose calculator scales your per-acre nutrient targets (nitrogen, phosphorus, potash) to the whole field. The defaults suit wheat at 50-35-25; switch them to 60-30-30 for rice or match your soil-test report exactly. Get the nutrient totals right first, then convert to urea and DAP bags with the companion tool.

  1. Enter your field area in acres.
  2. Enter the nitrogen, phosphorus and potash rates per acre (defaults are for wheat).
  3. For rice, change the rates to 60, 30 and 30.
  4. Click Calculate to see total N, P and K kilos for the field.

Formula

Total nutrient (kg) = field acres × rate per acre, computed separately for N, P and K.

Worked example

Five acres of wheat at 50-35-25: nitrogen = 250 kg, phosphorus = 175 kg, potash = 125 kg for the whole field. These totals feed directly into the urea/DAP bag calculator. A soil test every two to three years keeps these rates honest instead of repeating last season out of habit.

Frequently asked questions

A common recommendation is 50 kg nitrogen, 35 kg phosphorus and 25 kg potash per acre — adjust to your soil test.

Typically 60 kg nitrogen, 30 kg phosphorus and 30 kg potash per acre.

The soil test — blanket doses waste fertilizer where the soil already has enough of a nutrient.

Urea DAP Bag Calculator How many urea and DAP bags per acre? Convert nutrient needs into bag counts. Pesticide Dilution Calculator How much pesticide per litre of water? Get the exact dilution for your sprayer tank. Drip Irrigation Lateral Calculator Drip irrigation lateral length calculator for row crops — total pipe for your field layout.