Lawn Seed Calculator
Calculate exactly how many pounds of grass seed are needed to cover your lawn based on its size and the recommended seeding rate. Perfect for new lawn installations and overseeding thin or patchy turf.
About this calculator
Grass seed is sold by coverage area, with each grass variety having a recommended seeding rate in pounds per 1,000 square feet. The formula is: Seed (lbs) = (area / 1,000) × seed_rate, where area is your lawn size in square feet and seed_rate is the manufacturer's recommended rate. For example, Kentucky Bluegrass typically requires 2–3 lbs per 1,000 sq ft for a new lawn. Overseeding an existing lawn generally uses half the new-lawn rate. Using too little seed leads to patchy coverage, while using too much causes seedling competition and poor establishment. Always check the seed bag label for the specific rate of your grass variety.
How to use
You have a 4,500 sq ft lawn and want to overseed with tall fescue at a rate of 6 lbs per 1,000 sq ft. Seed needed = (4,500 / 1,000) × 6 = 4.5 × 6 = 27 lbs. So purchase at least 27 lbs of seed. If you were seeding a brand-new lawn at the higher new-lawn rate of 8 lbs per 1,000 sq ft, you'd need (4,500 / 1,000) × 8 = 36 lbs. Always round up to the nearest bag size and store any surplus in a cool, dry place.
Frequently asked questions
How much grass seed do I need per 1000 square feet for different grass types?
Seeding rates vary significantly by grass species. Fine fescues and bentgrass need only 3–5 lbs per 1,000 sq ft, while tall fescue and ryegrass typically need 6–9 lbs. Kentucky Bluegrass has very small seeds and requires only 2–3 lbs per 1,000 sq ft for new seeding. Warm-season grasses like Bermuda (hulled) need about 1–2 lbs per 1,000 sq ft. Always refer to the specific product label, as rates can differ between cultivars of the same species.
What is the difference between seeding rates for a new lawn versus overseeding?
A new lawn requires a higher seeding rate because seed must establish from bare soil with no existing turf to fill gaps. Overseeding — adding seed to an existing thin lawn — typically uses 50% of the new-lawn rate since existing grass provides some coverage. Using the full new-lawn rate when overseeding wastes seed and can lead to overcrowding of seedlings. Before overseeding, mow short and dethatch to improve seed-to-soil contact.
When is the best time of year to seed a lawn for the best germination results?
Cool-season grasses (fescue, bluegrass, ryegrass) germinate best when soil temperatures are between 50–65°F, making early fall the ideal seeding window in most northern climates. Spring is a secondary option but competes with weed germination. Warm-season grasses (Bermuda, Zoysia, St. Augustine) prefer soil temps above 65–70°F, making late spring to early summer optimal. Seeding outside the recommended window reduces germination rates and increases the risk of seedling failure.