How much grass seed do I need?
Seed is sold by the pound and applied at a rate per 1,000 square feet, so the math is: find your lawn area, divide by 1,000, and multiply by the seeding rate for your grass type. Starting a brand-new lawn uses the full rate; overseeding an existing lawn to thicken it uses roughly half. This calculator applies the right rate automatically based on the project and grass you select.
Grass seed calculation formula
Lawn area ÷ 1,000 × seeding rate = pounds of grass seed. For example, a 5,000-square-foot lawn seeded at 6 pounds per 1,000 square feet needs about 30 pounds of seed: 5,000 ÷ 1,000 × 6 = 30.
New lawn versus overseeding
A new lawn needs the full label rate because seed must establish across bare soil. Overseeding usually uses about half the new-lawn rate because existing grass already covers part of the area. Select the correct project in the calculator and always compare the result with the rate printed on your seed bag.
Seeding rates by grass type
Different grasses spread differently, so their rates vary. Fine-seeded, spreading types like Kentucky bluegrass and Bermuda need far less seed per square foot than bunch-type ryegrass. Use these typical new-lawn ranges as a guide, and always defer to the label on your specific bag.
| Grass | New lawn (lb/1,000 sq ft) |
|---|---|
| Tall fescue | ~6 |
| Perennial ryegrass | ~8 |
| Fine fescue | ~5 |
| Kentucky bluegrass | ~3 |
| Bermuda | ~1.5 |
Sod: rolls and pallets
Sod gives an instant lawn. It's sold by the square foot, in rolls or slabs that are bundled onto pallets covering about 450 square feet each. Because lawns are rarely perfect rectangles, add a waste allowance — more for curved or irregular edges — so you have enough to trim and fit.
Frequently asked questions
Is it cheaper to seed or lay sod?
Seed costs a fraction of sod per square foot, but you wait weeks for it to fill in and you have to keep it watered through germination. Sod is more expensive but usable almost immediately. Budget and timeline drive the choice.
When should I seed?
Cool-season grasses establish best in early fall; warm-season grasses prefer late spring. Seeding in the right window dramatically improves germination over fighting the weather.
Should I order extra?
Yes — a little extra seed lets you patch thin spots, and extra sod covers trimming and odd corners. The waste allowance above builds that cushion into the sod estimate.
Related lawn and landscaping calculators
Planning the rest of the project? Estimate planting quantities with the plant calculator, ground cover with the mulch calculator, or base material with the gravel calculator.