Grass Seed Calculator
Calculate how many pounds of grass seed you need by lawn area, species and use case (new lawn or overseeding).
The grass seed calculator returns the pounds of seed needed for a new lawn, overseeding an existing lawn or patching bare spots. Seeding rate varies dramatically by species: tall fescue and perennial ryegrass need 8 lbs per 1000 sq ft for new lawns, Kentucky bluegrass needs 3 lbs (the seeds are smaller and the rate looks lower but coverage is the same), Bermuda and zoysia need just 2 lbs because warm-season seeds are tiny. Overseeding uses half the new-lawn rate, while bare-patch repair uses double for fast fill-in. St. Augustine is the one common grass not sold as seed - it has to go down as sod or plugs.
Explore all our landscaping materials calculator tools, or browse the full construction & home improvement diy calculators.
Frequently asked questions
Tall fescue and perennial ryegrass: 8 lbs per 1000 sq ft for new lawns, 4 lbs for overseeding. Kentucky bluegrass: 3 lbs new / 1.5 lbs overseed. Bermuda and zoysia: 2 lbs new / 1 lb overseed. Sun & shade mixes: 6 lbs new / 3 lbs overseed. These are starting points - bag labels sometimes recommend slightly different rates depending on germination percentage.
For a brand new lawn of tall fescue, 8 lbs total. For overseeding the same area, 4 lbs. For bare patch repair (going down heavy to fill quickly), 16 lbs. Buy a 7 lb or 10 lb bag for new fescue lawns at this size - most home improvement stores stock bags in 3, 7, 20 and 50 lb sizes.
Seed is 5-10x cheaper but takes 2-3 months to establish and looks rough for the first growing season. Sod gives an instant lawn but costs $0.30-0.60 per sq ft installed. Choose sod for visible front yards where curb appeal matters, slopes where seed washes out, or when you need usable lawn fast. Choose seed for large areas, back yards or budget-driven projects.
Cool-season grasses (fescue, KBG, ryegrass): early fall (late August to mid-October) is the gold standard - warm soil, cool air and reliable rain. Spring is the second-best window. Avoid summer. Warm-season grasses (Bermuda, zoysia): late spring through early summer when soil reaches 70°F+. Avoid fall planting for warm-season grass - it cannot establish before dormancy.
Bare patches need fast, dense germination to crowd out weeds and erosion. Doubling the seed rate creates a thicker stand that fills in faster, even at the cost of some self-thinning later. For established lawns, doubling the rate just wastes seed - the existing grass crowds out extras. Patch repair is the only place where heavy seeding actually helps.