Tool
Grass Seed Calculator: How Much Seed for a New Lawn or Overseeding
Buying the right amount of seed saves money, and sowing at the right rate gives stronger grass than sowing heavily.
What changed
- : First published.
On this page
Where the rates come from
Rates are pounds of seed per 1,000 square feet, as published by university extension services. Small-seeded grasses such as Kentucky bluegrass and bermudagrass need far fewer pounds than large-seeded tall fescue and ryegrass, because each pound contains many more seeds (University of Tennessee).
| Grass | New lawn (lb / 1,000 sq ft) | Overseeding | Sources |
|---|---|---|---|
| Kentucky bluegrass | 2–3 | 1.5 | Ohio State, UC IPM, Maryland (overseed) |
| Tall fescue | 6–10 | 4 | Maryland 6–8; Illinois 6–9; Ohio State and UC IPM 8–10 |
| Fine fescue | 3–6 | 2.5 | Ohio State 3–6; Maryland 4–5 |
| Perennial ryegrass | 6–9 | not listed | Ohio State 7–8; UC IPM 6–9 |
| Bermudagrass, hulled | 0.5–1 | not listed | Tennessee 0.5–1; UC IPM 1 |
| Buffalograss | 1.5–2 | not listed | UC IPM |
Where sources differ, the calculator shows the combined range. Use the lower end for good-quality seed on a well-prepared bed, and the upper end for tough sites. Tennessee notes that unhulled bermudagrass seed needs about double the hulled rate.
Worked example
Example: 5,000 sq ft of new tall fescue
5,000 ÷ 1,000 = 5 units. 5 × 6 lb = 30 lb; 5 × 10 lb = 50 lb. Buy 30–50 lb, which is two 25 lb bags at the high end.
Overseeding the same area: 5 × 4 lb = 20 lb.
Pure live seed
Seed bags carry a tag listing purity (the share of the weight that is the named seed) and germination (the share expected to sprout). Multiplying them gives pure live seed (PLS). Ohio State explains how professionals use PLS to adjust rates. For home lawns, buying seed with high purity and germination and a recent test date is the simple fix; if your seed's PLS is low, stay toward the top of the range instead of piling on more.
Measuring your area
- Rectangles: length × width.
- Odd shapes: split into rectangles and triangles (base × height ÷ 2), or pace it out and accept a little error.
- Subtract beds, patios and the house footprint.
- Bare patches: measure each one; small areas add up.
Getting seed to grow
- Timing. Cool-season grasses do best seeded in late summer to early fall; warm-season grasses need warm soil, about 70°F and up. Check with the soil temperature planner and our seeding timing guide.
- Seed-to-soil contact. Rake or core-aerate first, spread half the seed in one direction and half crosswise (University of Maryland), then lightly rake or roll.
- Water. Keep the top inch moist until seedlings are established; that may mean light watering more than once a day in warm weather.
- Avoid pre-emergents. Most crabgrass pre-emergents also stop grass seed for the period on the label.
Common questions
How much grass seed do I need for 1,000 square feet?
It depends on the species: about 2 to 3 lb of Kentucky bluegrass, 6 to 10 lb of tall fescue, 3 to 6 lb of fine fescue or 6 to 9 lb of perennial ryegrass for a new lawn, according to the extension sources on this page.
Should I double the seed rate to be safe?
No. Illinois Extension warns that exceeding the rate can produce weak, spindly seedlings and more disease. Good soil contact and steady moisture matter more than extra seed.
Sources
- Ohio State University, Turfgrass Establishment Series: Species/Cultivar Selection
- UC IPM, Planting times and rates for seed
- Illinois Extension, Planting a New Lawn
- University of Maryland Extension, Lawn Renovation and Overseeding
- University of Tennessee, Turfgrass Establishment (W160-B)
Checked Nov 11, 2026. Spot an error? Tell us.