Grass Seed Coverage Calculator
Calculate the amount of grass seed needed to cover your lawn based on area, grass type, and seeding method.
Formula
Seed Required (lbs) = (Lawn Area (sq ft) ÷ 1,000) × Seeding Rate (lbs / 1,000 sq ft)
Bags Needed = ⌈ Seed Required ÷ Bag Size ⌉ (rounded up to nearest whole bag)
Lawn Area (sq ft) = Length (ft) × Width (ft)
Seeding rates vary by grass species and method. New lawn seeding requires approximately twice the seed of overseeding an existing lawn.
| Grass Type | New Lawn (lbs/1,000 sq ft) | Overseeding (lbs/1,000 sq ft) |
|---|---|---|
| Kentucky Bluegrass | 2.0 | 1.0 |
| Tall Fescue | 8.0 | 4.0 |
| Fine Fescue | 4.0 | 2.0 |
| Perennial Ryegrass | 8.0 | 4.0 |
| Bermudagrass | 1.5 | 0.75 |
| Zoysiagrass | 2.0 | 1.0 |
| St. Augustinegrass | 0.5 | 0.25 |
| Centipedegrass | 0.25 | 0.125 |
Assumptions & References
- Seeding rates are based on pure live seed (PLS) recommendations from university cooperative extension services (Penn State Extension, University of Georgia Extension, NC State Extension).
- Lawn area is calculated as a simple rectangle (Length × Width). For irregular shapes, calculate each section separately and sum the totals.
- Overseeding rates are approximately 50% of new lawn seeding rates, as existing turf provides partial coverage and competition.
- Bags needed are always rounded up to the nearest whole bag to ensure full coverage.
- Seeding rates assume good seedbed preparation, proper soil contact, and adequate moisture for germination.
- Warm-season grasses (Bermuda, Zoysia, St. Augustine, Centipede) are best seeded in late spring to early summer; cool-season grasses (Bluegrass, Fescue, Ryegrass) are best seeded in late summer to early fall.
- Actual seed requirements may vary based on seed quality (germination rate), soil conditions, slope, and local climate.
- For slopes or heavily shaded areas, increase seed rate by 10–25% to compensate for reduced germination success.
- This calculator does not account for seed mixes; if using a blend, use the rate for the primary grass species in the mix.