Grass Seed Calculator
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Seeding rates are typical figures, not label instructions. Follow the rate printed on your seed bag, which depends on the blend and seed quality.
Turn this into a quote
A one-page PDF for your customer, filled in from the numbers above. Your markup isn't shown.
How the grass seed calculation works
Pick the grass type and job
Seeding rates are given in pounds per 1,000 sq ft. Penn State Extension suggests 6–8 lb of turf-type tall fescue for a new lawn, so the calculator uses 7. NC State Extension suggests a 25–50% lower rate when seeding into an existing lawn, so overseeding tall fescue uses 4.
Seed = area ÷ 1,000 × rate
A 5,000 sq ft new tall fescue lawn needs 5 × 7 = 35 lb of seed.
Divide by the bag size and round up
35 lb in 25 lb bags is 1.4 bags, so buy 2. Coated seed weighs more, so check the label rate before you buy.
Price it: materials + labor, then markup
Add starter fertilizer and straw, then crew hours at your cost per hour. A 30% markup on cost is a 23% margin on the price.
Worked example. A 5,000 sq ft new tall fescue lawn at 7 lb per 1,000 sq ft needs 35 lb of seed, or 2 bags of 25 lb at $85 ($170). With $60 of starter fertilizer and straw, materials are $230. Add 4 labor hours at $45 ($180) for a cost of $410. A 30% markup prices the job at $533.
Grass Seed FAQ
How much grass seed do I need?
Multiply the lawn area in thousands of square feet by the seeding rate. A 5,000 sq ft new tall fescue lawn at 7 lb per 1,000 sq ft needs 35 lb. Overseeding the same lawn at 4 lb needs 20 lb.
How much grass seed per square foot?
Rates are quoted per 1,000 sq ft. For a new lawn, Penn State Extension lists 6–8 lb for tall fescue, 2–3 lb for Kentucky bluegrass, 4–5 lb for perennial ryegrass and 4–5 lb for fine fescue. NC State Extension lists 1–2 lb for bermudagrass and zoysiagrass and 0.25–0.5 lb for centipedegrass. 7 lb per 1,000 sq ft is 0.007 lb, or about 0.11 oz, per square foot.
How much grass seed to overseed a lawn?
NC State Extension suggests a 25–50% lower rate than for a new lawn when seeding into existing grass. For tall fescue at 7 lb that is about 3.5–5 lb per 1,000 sq ft; the calculator uses 4. Penn State lists 4–6 lb for overseeding with perennial ryegrass.
How much grass seed per acre?
An acre is 43,560 sq ft, so multiply the rate per 1,000 sq ft by 43.56. A new tall fescue lawn at 7 lb per 1,000 sq ft needs about 305 lb per acre. Kentucky bluegrass at 2 lb needs about 87 lb per acre.
How many square feet does a 50 lb bag of grass seed cover?
Divide 50 by the seeding rate and multiply by 1,000. At 7 lb per 1,000 sq ft, a 50 lb bag covers about 7,100 sq ft of new tall fescue lawn. At 4 lb for overseeding, it covers 12,500 sq ft.
Can I put down too much grass seed?
Yes. NC State Extension warns that higher seeding rates can give weak, thin stands that are more prone to disease and heat stress. Stick to the rate on the bag.
Why is the bag's rate different from this calculator?
Blends, coated seed and germination rates change how much you need. NC State notes that many seed coatings call for a higher rate because of the added weight. Type the rate from your bag into the seeding rate field.
Sources: Penn State Extension: Lawn establishment (seeding rates) · NC State Extension Gardener Handbook: Lawns (warm-season seeding rates) · NC State Extension: Carolina Lawns (overseeding at a 25–50% lower rate)