Grass Seed Calculator

It depends on species and purpose more than almost any other lawn calculation. This calculator asks for both: pick your grass species and whether you are seeding bare ground or overseeding an existing lawn, and it fills in a sourced rate in pounds per 1,000 square feet, then multiplies by the area you measure. Turf-type tall fescue needs roughly three times the seed Kentucky bluegrass does for the same new lawn, so skipping the species step and using one generic rate is the most common way people over or under order.

Between about 0.25 and 8 pounds, depending entirely on species and purpose, according to Penn State Extension and Clemson Cooperative Extension guidance. Kentucky bluegrass runs 2 to 3 pounds for a new lawn, turf-type tall fescue runs 6 to 8 pounds, and tiny-seeded centipedegrass runs only a quarter to a half pound. Pick your species in the calculator above rather than relying on a single generic number.

Multiply the per 1,000 square foot rate for your species by 43.56, since an acre is 43,560 square feet. For turf-type tall fescue at 6 to 8 lb per 1,000 sq ft, that works out to roughly 260 to 350 lb per acre. This calculator works directly in the area you enter, so for a large lot you can enter acres as the area unit and it converts automatically rather than requiring you to do that multiplication by hand.

Less than a new lawn needs, because existing turf already covers most of the ground and new seed only has to fill the gaps. Penn State Extension's own guidance shows this directly for perennial ryegrass: 3 to 5 lb per 1,000 sq ft for establishment against 2 to 5 lb for renovation into existing turf. Select "Overseeding" as the purpose in the calculator above and the rate field updates to the appropriate lower figure for your species automatically.

6 to 8 lb per 1,000 sq ft for a new lawn, per Penn State Extension, dropping to roughly 3 to 4 lb per 1,000 sq ft when overseeding into an existing tall fescue lawn. It is one of the higher rates among common lawn species because its seed is comparatively large and the plant produces fewer tillers than a spreading grass like bluegrass.

2 to 3 lb per 1,000 sq ft for a new lawn in a pure stand, per Penn State Extension, dropping to roughly 1 to 1.5 lb per 1,000 sq ft when overseeding. Bluegrass is slow to establish from seed compared with ryegrass or fescue, which is why it is frequently blended with a faster-germinating grass for early cover while it fills in by rhizome.

3 to 5 lb per 1,000 sq ft for a new lawn and 2 to 5 lb per 1,000 sq ft for overseeding, per Penn State Extension, which is a smaller gap between the two purposes than most other cool-season species because ryegrass germinates fast enough that it is commonly used specifically for quick overseeding repairs.

1 to 2 lb per 1,000 sq ft of hulled seed for a new lawn, per Clemson Cooperative Extension, roughly halving for overseeding. Bermudagrass seed is small and this is a light rate compared with cool-season grasses; the species compensates by spreading aggressively by stolon once it establishes.

1 to 2 lb per 1,000 sq ft, per Clemson Cooperative Extension, using a seeded cultivar such as Zenith. Most zoysia lawns are established from sod or plugs rather than seed, since zoysia spreads and fills in slowly regardless of establishment method, so a seeded lawn from this species takes patience even at the correct rate.

A quarter to a half pound per 1,000 sq ft, per Clemson Cooperative Extension, the lightest rate of any species on this page because centipedegrass seed is unusually tiny. Sowing it at a rate closer to a typical cool-season grass would waste most of the seed and produce a stand too dense for the species' naturally slow, low growth habit.

A new lawn rate assumes bare, prepared soil where every seed has to find open ground and establish with no competition. An overseeding rate assumes an existing lawn where living turf already covers most of the area and new seed only needs to thicken the gaps, so it runs noticeably lower, commonly around half the new-lawn figure for a given species. Select the correct purpose in the calculator above rather than applying a new-lawn rate to an overseeding job, which wastes seed and can crowd the existing turf.

By climate, not preference. Cool-season grasses, Kentucky bluegrass, tall fescue, perennial ryegrass and fine fescue, grow best in spring and fall and dominate lawns from the transition zone north. Warm-season grasses, bermudagrass, zoysiagrass and centipedegrass, grow best in summer heat and dominate lawns through the Deep South and Southwest. Planting the wrong season's grass for a given climate is a far more common and costly mistake than getting the seeding rate slightly off.

Calculate above and read the bag count straight off the results, at common 3, 7, 25 or 50 pound bag sizes. The panel also shows the total pounds needed and an editable per-pound price next to it, so you can compare a bagged price against a bulk or bin price without a separate conversion.

Yes. Every measurement field accepts metric or imperial units and converts automatically, including acres if you are seeding a large lot, and the results show both pounds and kilograms. The sourced seeding rates behind the numbers are unchanged regardless of which units you use, only the displayed units change.

This calculator is specifically for lawn turf species, seven common cool and warm-season grasses with sourced seeding rates by species and by new-lawn versus overseeding purpose. The Seed Calculator on this site covers broader, non-turf seeding, such as wildflower and pollinator meadow mixes or temporary erosion-control cover, where you enter a known rate from your own seed packet rather than picking from a lawn-grass species list.