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Fertilizer Calculator

A fertilizer calculator tells you how many bags of lawn feed to buy, based on your lawn size and the coverage printed on the bag. Enter your area and it does the matching, so you cover the whole lawn evenly without buying three bags when you needed two.

Your measurements

Result

Lawn fertilizer is a repeat purchase through the season, and the right amount matters: too little and the lawn stays patchy, too much and you can burn it. This sizes it to the bag's stated coverage.

How it is calculated

Bags = lawn area times the number of applications, divided by the coverage per bag, rounded up. Coverage is set by the product's nitrogen rate, so always go by the bag's stated square footage rather than guessing.

Steps

Measure your lawn area in square feet (length times width of each section, added up).
Enter the coverage per bag from the label - 5,000 sq ft is common.
Set how many applications you are buying for (a season is usually 3-4).
Read the number of bags to buy.
Apply with a spreader at the label rate for even coverage.

Worked example

A 5,000 sq ft lawn with a bag that covers 5,000 sq ft needs 1 bag per application. A 10,000 sq ft lawn needs 2 bags.

Common questions

How much fertilizer does my lawn need?

Divide your lawn area by the coverage per bag. Most lawn foods state a coverage like 5,000 or 15,000 sq ft.

How often should I fertilize?

Most cool-season lawns are fed 3-4 times a year - early spring, late spring, summer and fall. Warm-season lawns are fed through their growing season.

Can I apply too much?

Yes - over-application burns the lawn and pollutes runoff. Stay at the label rate; more is not better.

Do I need a spreader?

A broadcast or drop spreader gives even coverage and is worth it. Hand-spreading leaves greener and weaker stripes.