Grass Seed Calculator
Enter your lawn size to get the grass seed you need in pounds, plus an estimated cost.
Seed needed
Estimated cost
How to calculate grass seed
Grass seed is sold by the pound, and each pound covers a fixed area. Find the lawn area, divide by the coverage per pound, and round up.
Formula: pounds = lawn area (sq ft) ÷ coverage per pound, rounded up
Worked example: 100 ft × 50 ft lawn
Lawn area = 100 × 50 = 5,000 sq ft. At 250 sq ft per pound: 5,000 ÷ 250 = 20 lbs.
New lawn or overseeding?
New lawns need about twice as much seed as overseeding, because bare soil has no grass to fill in. Always check the bag label, since coverage varies by grass type.
Common lawn sizes
Cost tips
Prices on this page are editable estimates, not quotes. Get 2 to 3 local quotes before you buy, and ask if delivery is included. Delivery, tax and waste can change the total a lot. Order a little extra for cuts and breakage, and confirm final quantities with your supplier or a qualified professional.
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Frequently asked questions
How much grass seed do I need for a 100x50 lawn?
A 100 ft by 50 ft lawn needs 20 lbs of seed at 250 sq ft per pound.
How much area does a pound of seed cover?
About 250 sq ft for a new lawn and 500 sq ft for overseeding. Check the bag label, it varies by grass type.
New lawn or overseeding?
New lawns need about twice as much seed as overseeding. Enter the rate from your seed bag for an exact figure.
When should I seed?
Early autumn is best for cool-season grass. Spring works too, but weeds compete more.
Are the prices accurate?
Prices are editable estimates. The defaults are typical US figures, and your local price can be higher or lower.