About this calculator
Grass species have very different seed sizes — a pound of Kentucky bluegrass contains roughly five to ten times as many seeds as a pound of tall fescue — so the right amount of seed depends on what you’re planting. This calculator applies a typical seeding rate for each grass type to your lawn area and tells you how many pounds and bags to buy.
Overseeding a thin lawn uses roughly half the rate of seeding bare soil.
How to use it
- Enter the length and width of the lawn. For irregular yards, add up rectangles using the square footage calculator.
- Choose your grass type. Use the rate on your seed bag if it differs.
- Choose new lawn or overseeding.
- Enter the bag size you plan to buy.
The formula
Seed (lb) = lawn area (sq ft) ÷ 1,000 × seeding rate (lb per 1,000 sq ft)
Overseeding rate = new-lawn rate ÷ 2
New-lawn rates used, in pounds per 1,000 sq ft: tall fescue 7, perennial ryegrass 6, sun & shade mix 5, fine fescue 4, Kentucky bluegrass 2, bermudagrass and zoysia 1.5, centipede 0.5. These are mid-range figures from university extension guides and seed labels; always check the label on your product.
Worked example
These are the calculator’s starting values and the results they produce:
| Lawn length | 50 ft |
|---|---|
| Lawn width | 40 ft |
| Grass type | Tall fescue |
| Project | New lawn (bare soil) |
| Bag size | 7 lb |
Tips before you buy
- Seed cool-season grasses (fescue, bluegrass, rye) in early fall; warm-season grasses (bermuda, zoysia, centipede) in late spring.
- Split the seed in half and spread it in two perpendicular passes for even coverage.
- Rake seed lightly into the top ¼ in of soil and keep it consistently moist until it’s established.
- More seed isn’t better: overcrowded seedlings compete and are more prone to disease.
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends on the grass: about 7 lb of tall fescue, 6 lb of perennial ryegrass, 2 lb of Kentucky bluegrass or 1.5 lb of hulled bermudagrass per 1,000 sq ft for a new lawn. Use about half that for overseeding.
How much grass seed do I need for an acre?
An acre is 43,560 sq ft, so multiply the per-1,000 rate by 43.56 — for tall fescue that is about 305 lb for a new lawn.
How much grass seed for a 2,000 sq ft lawn?
About 14 lb of tall fescue for a new lawn, or 7 lb for overseeding.