Grass Seed Calculator
Calculate grass seed needed by lawn area, grass type, and seeding method.
Covers 8 species including bluegrass, fescue, ryegrass, bermuda, and zoysia.
Grass seed coverage rates vary more than most people expect: from 0.5 lbs per 1,000 sq ft for centipede grass to 8 lbs per 1,000 sq ft for tall fescue. The difference comes down to seed size. Centipede seeds are tiny; tall fescue seeds are comparatively large and need to be broadcast densely to achieve adequate coverage.
The formula is: pounds needed = (lawn area / 1,000) × seed rate.
New seeding vs overseeding
New seeding on bare soil uses roughly twice the seed of overseeding. On bare dirt, every square inch needs a seed nearby. Overseeding an existing lawn is a lighter application meant to thicken up thin areas.
The most common overseeding mistake: doing it too early in the season when the existing grass is still growing aggressively. The established turf outcompetes the new seedlings for light and water. For cool-season grasses, early fall is the ideal window — soil is warm enough for germination, air is cooling, and the existing grass slows down enough to give new seed room.
Grass type notes
Kentucky Bluegrass germinates slowly (14-30 days) and requires consistent moisture during establishment, but produces a dense, attractive lawn for northern climates.
Tall fescue establishes faster and tolerates drought better. It is the workhorse grass for transition zones where it is too hot for bluegrass but too cold for warm-season species.
Bermuda and zoysia are warm-season grasses that go dormant and brown in winter. They spread aggressively once established, so precise seed coverage is less critical than for bunch-type grasses.
Centipede grass is a low-maintenance warm-season option common in the Southeast. Its extremely low seed rate reflects the physical size of the seeds, not a lower coverage requirement.
After seeding, keep the seedbed consistently moist until germination. Even a single drying-out event during the first two weeks can kill germinating seeds that have already cracked open.