Buying too little grass seed means a thin, patchy lawn and a second trip to the store. Buying too much means wasted money and seedlings crowded so tight they get diseased. Enter your lawn size and grass type below for the exact pounds of seed you need — for a brand-new lawn or for overseeding.
Grass Seed Calculator
Rates are typical ranges — always check your seed bag, since coated and premium blends vary.
After sowing, check grass seed germination times so you know when to expect sprouts.
Seeding Rates by Grass Type
Not all grass seed is equal — a pound of tiny Kentucky bluegrass seed contains far more seeds than a pound of big tall fescue seed, so each type has its own rate, measured in pounds per 1,000 square feet:
| Grass type | New lawn (lbs / 1,000 sq ft) | Overseeding (lbs / 1,000 sq ft) |
|---|---|---|
| Kentucky Bluegrass | 2–3 | 1–2 |
| Tall Fescue | 8–10 | 4–5 |
| Perennial Ryegrass | 5–9 | 4–5 |
| Fine Fescue | 4 | 2 |
| Bermuda | 1–2 | 0.5–1 |
| Zoysia | 2 | 1 |
| Centipede | 0.5 | 0.25 |
| Bahia | 8 | 4 |
| Buffalo grass | 3 | 1.5 |
The calculator above uses the midpoint of each range. These are typical rates — always check your seed bag, since coated and premium blends can vary quite a bit. If you're still choosing a variety, see our guide to the fastest growing grass seed and the best grass seed for shaded areas.
How the Math Works
The formula is simple: (lawn area in sq ft ÷ 1,000) × seeding rate = pounds of seed
Worked example: you have a 5,000 sq ft lawn and you're planting tall fescue from scratch. Tall fescue's new-lawn rate is about 10 lbs per 1,000 sq ft: (5,000 ÷ 1,000) × 10 = 50 lbs. Overseeding that same lawn? Use the overseeding rate of about 5 lbs per 1,000 sq ft: (5,000 ÷ 1,000) × 5 = 25 lbs. That's all the calculator is doing — it just saves you the arithmetic and looks up the right rate for your grass type.
How to Measure an Irregular Lawn
Few lawns are perfect rectangles. For L-shaped or curvy lawns, break the area into simple shapes, calculate each one, and add them up:
- Rectangles: length × width
- Circles: 3.14 × radius × radius (measure a round bed or tree ring)
- Triangles: (base × height) ÷ 2
Sketch it on paper, label each section with its square footage, and total them. For the detailed walkthrough with diagrams, use our lawn square footage calculator. And if you're weighing seed against sod for a new lawn, compare costs and effort with our sod calculator.
New Lawn vs Overseeding — Why the Rate Halves
A new lawn starts from bare soil: every single blade has to come from your seed, so you sow at the full rate for thick, even coverage. When you overseed, mature grass plants already occupy most of the ground — the new seed only needs to fill thin spots and thicken things up. That's why the overseeding rate is roughly half.
One caution: "half" assumes your existing lawn is reasonably healthy. If it's more bare dirt than grass, treat it closer to a new lawn. Our guide on how to overseed a lawn without aerating walks through the whole process.
Frequently Asked Questions
How much grass seed do I need per 1,000 square feet?
It depends on the type: Kentucky bluegrass needs 2–3 lbs, tall fescue 8–10 lbs, and perennial ryegrass 5–9 lbs for a new lawn. Overseeding uses about half those rates. The table above covers nine common grass types.
How do I calculate grass seed for my lawn?
Divide your lawn's area in square feet by 1,000, then multiply by the seeding rate for your grass type. Example: 5,000 sq ft of tall fescue at 10 lbs per 1,000 = 50 lbs of seed. Or just use the calculator at the top of this page.
How much grass seed per square foot?
Divide the per-1,000 rate by 1,000. Tall fescue at 10 lbs per 1,000 sq ft works out to about 0.01 lb per square foot — but it's far more practical to measure the whole lawn than to think per-foot.
Do I need less seed for overseeding?
Yes — about half the new-lawn rate, since the existing grass fills in most of the ground and the new seed only thickens thin areas.
How many square feet does a bag of grass seed cover?
Divide the bag's weight by your grass type's rate per 1,000 sq ft, then multiply by 1,000. Example: a 10 lb bag of tall fescue (10 lbs per 1,000 rate) covers about 1,000 sq ft of new lawn — or 2,000 sq ft of overseeding.
Can you put down too much grass seed?
Yes. Overcrowded seedlings compete for light, water, and nutrients, and the damp, airless conditions invite disease. More seed does not mean a thicker lawn — stick to the recommended rate for your grass type.
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