Lawn Seed Coverage Calculator
Find out exactly how many pounds of grass seed you need for your yard.
Lawn area
Seed type & application
Adjust if your lawn isn't a simple rectangle.
Your estimate
Seed to buy
—
lbs
Lawn area
—
sq ft
Effective area
—
sq ft
Total area (L × W)—
Shape adjustment—
Effective seeding area—
Seed rate (per 1,000 sq ft)—
Application multiplier—
Total seed required—
How to use this lawn seed calculator
Enter your lawn's length and width in feet, select your grass seed type, and choose whether you're seeding a new lawn or overseeding an existing one. If your lawn isn't a rectangle, use the shape adjustment to get a more accurate estimate.
Seed rates vary significantly by grass type — Kentucky bluegrass needs far less seed per 1,000 sq ft than ryegrass. Always check the bag for the manufacturer's recommended rate, as premium coated seeds may differ from the base rates used here.
Frequently asked questions
When is the best time to seed a lawn in the US?
Cool-season grasses (fescue, bluegrass, ryegrass) seed best in early fall (late August to October) or early spring. Warm-season grasses (bermuda, zoysia) prefer late spring once soil temps reach 65°F.
What's the difference between seeding and overseeding?
Seeding is establishing a new lawn from bare soil and uses the full seed rate. Overseeding is spreading seed over an existing lawn to thicken it or fill bare patches — you only need about half the seed rate since existing grass is already present.
Should I add extra seed as a buffer?
Yes — buy 10% more than the calculator suggests. Birds, washout, poor germination spots, and uneven spreading all reduce effective coverage. Having a little extra on hand means you can touch up thin areas without a second trip to the store.
How do I measure an irregular lawn?
Measure the longest length and widest width, then use the shape adjustment in this calculator. For very complex shapes, break the lawn into smaller rectangles, calculate each separately, and add the results together.