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Lawn Dominators

Fertilizer calculator

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Reviewed May 9, 2026

Lawn fertilizer calculator guide

Fertilizer math should start with target nutrient rate, product analysis, and lawn square footage. The app keeps the math and the record in the same place.

Calculate fertilizer amount

Enter your lawn size, target rate, and bag analysis.

The core fertilizer formula

Purdue Turfgrass explains the basic two-step math: divide the desired pounds of nutrient per 1,000 square feet by the nutrient percentage, then multiply by the treated area. For example, a 0.75 lb nitrogen target with a 16% nitrogen product needs 0.75 ÷ 0.16 = 4.69 lb of product per 1,000 square feet.

Why a calculator beats guessing

  • It separates actual nitrogen from product weight.
  • It scales the rate to your real lawn square footage.
  • It helps avoid accidental over-application when switching products.
  • It creates a log so you know what was applied and when.

Use Lawn Dominator

Use Lawn Dominator to calculate treatment amounts, save the product, log the date and rate, and compare results with photos over the season.

Research and extension sources

  1. Purdue Turfgrass: Calculating the Pounds of Fertilizer to Apply
  2. Purdue Turf Fertilizer Calculator