Grass Seed Calculator
Grass seed is applied at a rate per 1,000 square feet that depends on the species and whether you're starting a new lawn or overseeding. Enter your area and the rate for the pounds to buy.
Grass seed
4lb
- Lawn area
- 1,000 sq ft
How these numbers are worked out
The formula
Pounds of seed = (area ÷ 1,000) × the seeding rate. The rate is the variable that matters: it's set by the grass species and the job, so use the figure on your seed bag. Typical new-lawn rates are about 6–8 lb/1,000 sq ft for tall fescue, 5–9 for ryegrass, and 2–3 for Kentucky bluegrass; overseeding an existing lawn uses roughly half.
Constants and sources
- Pounds = (area ÷ 1,000) × seeding rate. The rate is species/job-specific (editable, from the seed bag); typical ranges follow common cooperative-extension seeding guidance.
How it was checked
Last reviewed . Before this calculator was published, its formula, constants and worked example were checked in a separate, AI-assisted review that redid the arithmetic and tested the factual claims; the site owner then approved it for publishing. No engineer or tradesperson reviews these pages. Where a figure depends on the product (a density, a coverage rate, a bag size), it is either an input you can change above or a fixed planning value stated on this page, so check it against your product's label or your supplier.
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Worked example
1,000 sq ft at 4 lb per 1,000 sq ft: (1,000 ÷ 1,000) × 4 = 4 lb of seed.
FAQs
- What seeding rate should I use?
- Use the rate printed on your seed bag — it's matched to that species and blend. As a guide for a new lawn: tall fescue ~6–8, perennial ryegrass ~5–9, Kentucky bluegrass ~2–3 lb per 1,000 sq ft. Over-seeding (thickening an existing lawn) uses about half the new-lawn rate.
- Does sowing more seed grow a thicker lawn?
- No — over-sowing makes seedlings compete for water, light, and nutrients, which weakens the stand and invites disease. Stay near the recommended rate; thickness comes from good soil prep, watering, and the right species, not from dumping extra seed.
- When should I plant?
- Cool-season grasses (fescue, rye, bluegrass) do best sown in early fall, with spring second; warm-season grasses (Bermuda, zoysia) go down in late spring into early summer. Good seed-to-soil contact and consistent moisture matter more than the exact pound count.