Lawn Seed Calculator
Find how much grass seed your lawn needs.
New lawn ~5, overseed ~3
Results update as you type.
How it works
Seeding a lawn with the right amount of grass seed is important for a healthy, even turf, and this calculator tells you how much to buy. You enter your lawn area and the seeding rate, and it returns the pounds of grass seed needed. Seed is applied at a rate expressed in pounds per 1,000 square feet, and the calculation simply scales that rate to your area. The correct rate depends on the situation and the grass type. Starting a brand-new lawn from bare soil requires a higher rate, often around 4 to 6 pounds per 1,000 square feet for common cool-season grasses, to establish full coverage. Overseeding an existing lawn to thicken it or fill thin spots uses a lower rate, typically around 2 to 4 pounds per 1,000 square feet, since the existing grass fills much of the space. Different grass species also have different recommended rates; fine fescues and ryegrasses differ from Kentucky bluegrass, for example, so check the seed bag for the manufacturer's guidance. Applying too little seed leaves sparse, patchy grass, while too much causes seedlings to compete and grow weak, so hitting the right rate matters. Measure your lawn area accurately, subtracting driveways, beds, and buildings. Enter your area and seeding rate to find the pounds of seed needed.
Pounds = (area / 1000) × seeding rate
Grass seed is applied at a rate given in pounds per 1,000 square feet, which varies by grass type and whether you are starting a new lawn or overseeding an existing one. Dividing your lawn area by 1,000 and multiplying by the rate gives the total pounds of seed needed.
Source:Lawn care guidelines
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter lawn area.
- 2
Adjust the options
Adjust seeding rate if they apply — sensible defaults are already set.
- 3
Read your result
Grass seed needed updates instantly as you type — no button to press.
Frequently asked questions
How much grass seed do I need?
Divide your lawn area by 1,000 and multiply by the seeding rate in pounds per 1,000 square feet. For a 2,000-square-foot new lawn at 5 pounds per 1,000, you need 10 pounds. The rate depends on grass type and whether you are seeding new ground or overseeding, so check the seed bag for guidance.
What seeding rate should I use?
For a new lawn from bare soil, use a higher rate, often 4 to 6 pounds per 1,000 square feet for common cool-season grasses. For overseeding an existing lawn, use a lower rate of about 2 to 4 pounds per 1,000, since established grass fills much of the area. Always check your specific seed's recommended rate.
What happens if I use too much seed?
Applying too much grass seed causes seedlings to compete with each other for water, light, and nutrients, producing thin, weak, and disease-prone grass rather than a lush lawn. More seed does not mean a better lawn. Following the recommended rate gives seedlings enough space to establish strong, healthy roots and even coverage.
What happens if I use too little seed?
Too little seed results in a sparse, patchy lawn with bare spots where weeds can take hold. Establishing full coverage becomes slow and uneven. Hitting the recommended rate ensures enough seedlings emerge to form a dense turf that crowds out weeds and looks uniform, which is why measuring area and rate accurately matters.
How do I measure my lawn area?
Measure the length and width of your lawn and multiply for rectangular areas, breaking irregular shapes into simpler sections and adding them. Subtract non-grass areas like driveways, flower beds, patios, and the house footprint. Accurate area measurement ensures you buy the right amount of seed rather than running short or overbuying.