Grass Seed Calculator
Work out how much grass seed or sod you need for a new lawn or overseeding.
About the Grass Seed Calculator
Seeding rates depend on seed size: Kentucky bluegrass seed is tiny, so 2–3 lb per 1,000 ft² is enough, while tall fescue and perennial ryegrass need 6–9 lb. Overseeding a thin lawn uses about half the new-lawn rate. Rates here are mid-points of typical US university extension recommendations; follow the seed bag for mixes.
The formula
Seed (lb) = area (ft²) ÷ 1000 × rate; 1 lb/1000 ft² = 4.88 g/m²
Typical seeding rates (lb per 1,000 ft²)
| Grass | New lawn | Overseed |
|---|---|---|
| Kentucky bluegrass | 2.5 | 1.5 |
| Tall fescue | 7 | 4 |
| Perennial ryegrass | 8 | 4.5 |
| Fine fescue | 4.5 | 2.5 |
| Bermudagrass (hulled) | 1.5 | 1 |
| Zoysiagrass | 1.5 | 1 |
| Centipedegrass | 0.4 | 0.25 |
| Bahiagrass | 7 | 4 |
Worked example
Example: Seed needed = 15.4 lb (6.99 kg)
- Inputs: Lawn area: 2,200; Area in: ft²; Grass: Tall fescue; Job: New lawn.
- Formula: Seed (lb) = area (ft²) ÷ 1000 × rate; 1 lb/1000 ft² = 4.88 g/m²
- Result: Seed needed = 15.4 lb (6.99 kg)
Questions people ask
Best time to seed?
Early autumn for cool-season grasses; late spring for warm-season grasses.
More seed for a thicker lawn?
Too much causes crowding and disease; stick to the rate.