Most lawns need between about 1 and 8 pounds of grass seed per 1,000 square feet, depending on the grass. For a new lawn on bare soil, university extension services list about 6 to 8 lb for turf-type tall fescue, 2 to 3 lb for Kentucky bluegrass, 4 to 5 lb for perennial ryegrass and fine fescue, and 1 to 2 lb for hulled bermudagrass or zoysiagrass. Overseeding an existing lawn takes about half as much. A 2,000 sq ft tall fescue lawn, for example, needs about 14 lb of seed (2 × 7).
To skip the math, enter your lawn size and grass type in the Grass Seed Calculator. It gives pounds of seed, bags and the area each bag covers.
The formula
Grass seed is sold by weight, and seeding rates are quoted in pounds per 1,000 square feet. So the math is:
- Pounds of seed = lawn area (sq ft) ÷ 1,000 × seeding rate (lb per 1,000 sq ft)
- Bags needed = pounds of seed ÷ bag size, rounded up
- Area one bag covers = bag size ÷ seeding rate × 1,000
How to measure your lawn
For a rectangle, multiply length by width. For a circle, use π × (diameter ÷ 2)². For an irregular lawn, split it into rectangles and circles, work out each area and add them together, then subtract the house, driveway and any beds you will not seed. The area formulas are the same ones explained in square feet to cubic yards.
Seeding rates by grass type
The table shows the new-lawn ranges published by university extension services, the planning value the Grass Seed Calculator uses (the middle of each range), and the overseeding value for the cool-season grasses, which is about half the new-lawn rate.
| Grass type | New lawn (lb per 1,000 sq ft) | Planning value | Overseeding | Source |
|---|---|---|---|---|
| Turf-type tall fescue | 6–8 | 7 | 3.5 | Penn State Extension |
| Kentucky bluegrass | 2–3 | 2.5 | 1.25 | Penn State Extension |
| Perennial ryegrass | 4–5 | 4.5 | 2.25 | Penn State Extension |
| Fine fescue | 4–5 | 4.5 | 2.25 | Penn State Extension |
| Bermudagrass (hulled) | 1–2 | 1.5 | Check your bag | NC State, UF/IFAS, Virginia Tech |
| Zoysiagrass | 1–2 | 1.5 | Check your bag | NC State, Virginia Tech |
| Centipedegrass | 0.25–0.50 | 0.375 | Check your bag | NC State, Virginia Tech |
Sources do not all agree. For example, Purdue lists 6 to 9 lb for turf-type tall fescue and 2 lb for Kentucky bluegrass, while NC State lists 1 to 2 lb for Kentucky bluegrass. Treat the table as a planning guide and follow the rate printed on your seed bag.
How much seed for your lawn size
Pounds of seed for a new lawn, using the planning values above. Overseeding takes about half of these amounts for cool-season grasses.
| Grass type | 1,000 sq ft | 2,000 sq ft | 5,000 sq ft | 10,000 sq ft |
|---|---|---|---|---|
| Turf-type tall fescue | 7 | 14 | 35 | 70 |
| Kentucky bluegrass | 2.5 | 5 | 12.5 | 25 |
| Perennial ryegrass | 4.5 | 9 | 22.5 | 45 |
| Fine fescue | 4.5 | 9 | 22.5 | 45 |
| Bermudagrass (hulled) | 1.5 | 3 | 7.5 | 15 |
| Zoysiagrass | 1.5 | 3 | 7.5 | 15 |
| Centipedegrass | 0.38 | 0.75 | 1.88 | 3.75 |
For an acre (43,560 sq ft), multiply the 1,000 sq ft figure by 43.56. For turf-type tall fescue that is about 305 lb for a new lawn.
How much one bag covers
Divide the bag weight by the seeding rate and multiply by 1,000. Here is the coverage of common bag sizes for turf-type tall fescue, using 7 lb per 1,000 sq ft for a new lawn and 3.5 lb for overseeding.
| Bag size | New lawn | Overseeding |
|---|---|---|
| 5 lb | 714 sq ft | 1,429 sq ft |
| 10 lb | 1,429 sq ft | 2,857 sq ft |
| 25 lb | 3,571 sq ft | 7,143 sq ft |
| 50 lb | 7,143 sq ft | 14,286 sq ft |
Bag sizes vary by brand, so check the weight printed on yours.
Worked examples
- 2,000 sq ft, tall fescue, new lawn: 2,000 ÷ 1,000 × 7 = 14 lb. That is two 10 lb bags (20 lb), or a 10 lb and a 5 lb bag (15 lb).
- 5,000 sq ft, tall fescue, overseeding: 5 × 3.5 = 17.5 lb, which fits in one 20 lb bag.
- 30 ft round bed, Kentucky bluegrass, new lawn: the area is π × 15² = about 707 sq ft, so 707 ÷ 1,000 × 2.5 = about 1.8 lb.
- 3,000 sq ft, hulled bermudagrass, new lawn: 3 × 1.5 = 4.5 lb.
New lawn vs overseeding
Overseeding an existing lawn uses less seed than starting on bare soil. K-State Research and Extension recommends about half the new-lawn rate, which for tall fescue is 3 to 4 lb per 1,000 sq ft. The University of Missouri also recommends 3 to 4 lb of pure live seed for tall fescue overseeding, which works out to about 3.5 to 4.5 lb of purchased seed at typical germination, and the University of Maryland lists 4 lb. Overseeding practices for warm-season lawns vary more, such as winter overseeding with ryegrass, so use the rate printed on your bag for those.
Why your seed bag matters
- Blends and mixes: a mix has its own rate. If the bag gives one, use it instead of the single-grass numbers above.
- Seed quality: the label shows purity and germination. Pure live seed combines the two, and rates are often written for pure live seed, so a lower-quality bag can need a little more by weight.
- Hulled and coated seed: the bermudagrass rate above is for hulled seed. Virginia Tech lists 5 to 10 lb per 1,000 sq ft for unhulled bermudagrass, and NC State notes that coated seed may need about double the rate.
Should I add extra seed?
The rates above are written to give a full lawn, so you do not need much on top. Some people add a small allowance for spreader overlap or patchy ground. The calculator has an optional extra selector (5%, 10% or 15%) if you want one, and it defaults to 0% so the result reflects only your measurements.
Common questions
How much grass seed per square foot?
At 7 lb per 1,000 sq ft (tall fescue, new lawn) that is 0.007 lb per square foot, or about 0.11 oz. At 2.5 lb per 1,000 sq ft (Kentucky bluegrass) it is 0.0025 lb, or about 0.04 oz.
How much seed for 5,000 square feet?
About 35 lb of tall fescue for a new lawn, 12.5 lb of Kentucky bluegrass, 22.5 lb of perennial ryegrass or 7.5 lb of hulled bermudagrass. For overseeding cool-season grass, use about half.
How many bags do I need?
Divide the pounds you need by the bag size and round up. For 14 lb of seed in 10 lb bags, 14 ÷ 10 = 1.4, so you need 2 bags.
Bottom line
Multiply your lawn area in square feet by your grass’s rate and divide by 1,000: for a new tall fescue lawn that is about 7 lb per 1,000 sq ft, and about half that for overseeding. Check the rate on your bag, since sources and products differ. To turn your measurements into pounds, bags and cost, use the Grass Seed Calculator. Deciding when to sow? See when to plant grass seed. Preparing bare ground first? The Topsoil Calculator works out how much soil to add. Comparing seed with turf? See the Sod Calculator, how to lay sod and how often to water new sod.
Sources
- Penn State Extension: Lawn Establishment
- NC State Extension Gardener Handbook: Lawns
- UF/IFAS: Bermudagrass for Florida Lawns
- Virginia Tech: Agronomy Handbook, Turfgrass
- K-State Research and Extension, Johnson County: Lawn Seeding in the Fall
- University of Missouri: Replenish Your Lawn With More Lawn
- University of Maryland Extension: Lawn Renovation and Overseeding
- Purdue Extension: Turfgrass seed (AY-25-W)