Grass Seed Calculator
A grass seed calculator tells you how much seed a lawn needs. It takes the lawn size, the seed type, and whether you are starting a new lawn or overseeding an existing one, and returns the pounds of seed and the cost. Type the lawn size below and pick a seed. Everything runs in your browser, with no signup.
Updated for 2026Your lawn
Seeding rates by grass type
Pounds per 1,000 square feet for a new lawn. Overseeding uses about half. Tap a row to load that seed.
| Seed type | New lawn rate | Overseed rate | Best for |
|---|
How the seed amount is calculated
Grass seed is applied at a rate of pounds per 1,000 square feet that depends on the seed type. Divide the lawn area by 1,000 and multiply by the rate:
A new lawn on bare soil uses the full rate for complete cover. Overseeding an existing lawn to thicken it uses about half the rate. Sowing much heavier than recommended makes seedlings compete and weakens the lawn, so stay close to the rate.
- Lawn50 ft × 40 ft
- Area (50 × 40)2,000 ft²
- SeedTall fescue, new lawn
- Rate7 lb / 1,000 ft²
- Seed (2,000 ÷ 1000 × 7)14 lb
- Overseed instead (half rate)7 lb
- Seed cost (14 × $4)$56
Frequently asked questions
How much grass seed do I need?
How much seed per 1,000 square feet?
New lawn or overseeding?
Can I use too much seed?
Does this calculator store my numbers?
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