Grass Seed Calculator
Work out how many pounds and bags of grass seed you need for a new lawn or to overseed a thin one.
How to use this grass seed calculator
Choose your lawn's shape and enter its size in feet. Then pick the grass type and whether you're starting a new lawn or overseeding an existing one. Overseeding uses about half the new-lawn rate. The amounts in the menu are pounds of seed per 1,000 square feet, and they're typical figures. The rate printed on your seed bag is always the best guide, so go with it if it's different.
Typical seeding rates
| Grass | New lawn (lb per 1,000 sq ft) | Best climate |
|---|---|---|
| Tall fescue | 7–9 | Cool and transition zones |
| Kentucky bluegrass | 2–3 | Cool, northern |
| Perennial ryegrass | 6–8 | Cool; quick to sprout |
| Fine fescue | 4–5 | Shady, cool |
| Bermuda (hulled) | 1–2 | Hot, southern, full sun |
The math behind it
Pounds of seed = lawn area ÷ 1,000 × the seeding rate × (1 for a new lawn, or 0.5 for overseeding). Bags = pounds ÷ bag size, rounded up.
Example: a 50 × 100 ft lawn is 5,000 sq ft. Seeding it with tall fescue at 8 lb per 1,000 sq ft takes 40 lb of seed, which is 6 bags of 7 lb or 2 bags of 20 lb.
Often used together
Quick answers
How much grass seed do I need per 1,000 square feet?
It depends on the grass. Tall fescue needs about 7–9 lb per 1,000 sq ft for a new lawn, Kentucky bluegrass only 2–3 lb, and Bermuda about 1–2 lb. Overseeding uses about half those amounts.
Is it bad to put down too much grass seed?
Yes. Seedlings that are packed too close compete for water and light, and the lawn ends up weaker and more prone to disease. Stick to the rate on the bag.
When is the best time to plant grass seed?
Early fall for cool-season grasses, and late spring to early summer for warm-season grasses such as Bermuda and zoysia.