Grass Seed Calculator
Estimate seed by lawn size without hiding the application-rate assumption. Use a source-labeled species range or enter the rate from your seed label or local guidance.
How much grass seed do I need?
The amount depends on lawn area and the seeding rate for the species or blend you are using. Measure the area first, then apply the rate shown on the seed label or a relevant source range. The calculator converts that combination into pounds and, when bag size is entered, whole bags.
How the seed calculation works
The calculator multiplies lawn area by a seeding rate expressed in pounds per 1,000 square feet. Source presets are displayed as ranges because species recommendations and regional conditions can differ.
seed (lb) = area (ft²) ÷ 1,000 × rate (lb / 1,000 ft²)
Why this calculator gives a range
A single national number would create false precision. The launch presets are sourced from Penn State Extension and remain clearly labeled. If your bag label or local extension guidance gives a different rate, choose Custom rate and use that value instead.
Before buying seed
Check the grass species or blend on the bag and compare its label rate with any source preset shown here. New-establishment and renovation rates can differ, and local climate or extension guidance may be more relevant than a general reference. Use Custom whenever you have a project-specific rate.