Read your seed label first

The area of your lawn is only half the calculation. The other half is the seed rate for your grass mixture and the work you are doing.

New lawns and overseeding use different rates

Starting a lawn on prepared ground and adding seed to an established lawn are different jobs. Look for the corresponding rate on your seed package. Do not use the higher number simply because you want faster or thicker results.

The MyYardCalc calculator starts with an example rate of 5 lb per 1,000 square feet. Replace it with the rate for your product. That starting value is not a recommendation for a particular grass, climate, or season.

Measure the area you will seed

Multiply length by width for rectangular sections. Break an irregular lawn into smaller shapes and add them. Exclude paths, beds, buildings, and any grass areas that are outside the project.

For example, a 2,500-square-foot lawn at a selected rate of 4 lb per 1,000 square feet needs 10 lb of seed. This is the calculated seed weight before adapting it to the package sizes available in the shop.

Regional examples show why the rate matters

The University of Maryland Extension gives the following guidance for its region. These examples illustrate differences between species and project types; they are not a universal prescription for every US lawn.

All rates in this table are pounds of seed per 1,000 square feet. Follow the seed label and guidance appropriate to your location and conditions.

Check the units before entering a rate

Our US setting expects pounds per 1,000 square feet. The metric setting expects grams per square meter and returns kilograms. A package that quotes coverage for the whole bag may require a small conversion.

If a 20 lb bag is labeled to cover 5,000 square feet for your intended use, the implied rate is 20 ÷ 5,000 × 1,000 = 4 lb per 1,000 square feet. Check that the coverage you use is for new seeding or overseeding as appropriate.

Buying and spreading are separate steps

The calculation estimates seed weight. It does not set your spreader. Follow the product and spreader instructions for calibration and application. If you divide the application into passes, divide the total seed between those passes rather than applying the full quantity each time.

Choose package sizes that provide enough for the calculated amount. Do not automatically spread every remaining seed just because the package is larger than your estimate.

Calculate your seed amount →