Enter your lawn size and grass type to get the pounds of seed you need — for a new lawn or overseeding.
How grass seed is worked out
Different grasses are sown at very different rates, so this grass seed calculator adjusts by grass type and whether you’re starting a new lawn or overseeding an existing one. Enter your lawn’s size and it returns the pounds of seed and a bag estimate.
New lawns need roughly double the seed of an overseed, and the calculator uses typical rate ranges for each grass type.
A worked example
As an example, with a length of 50, width of 30, diameter of 30, the calculator returns a grass seed of 6. Underneath, Lawn area comes out at 1,500 ft² and Seeding rate at 4 lb / 1000 ft². Change any field and every figure updates as you type.
Step by step
- Enter your lawn area, rectangular or round.
- Pick your grass type and whether it’s a new lawn or overseed.
- Read the pounds of seed and bag count, and add a price for cost.
The maths behind it
seed (lb) = area ÷ 1000 × seeding rate
new lawn uses the higher rate · overseeding the lower
Frequently asked questions
How much grass seed do I need?
It depends on the grass and job. New lawns typically use 4–9 lb per 1,000 ft² depending on type; overseeding uses roughly half that.
What’s the best time to seed a lawn?
Early autumn is ideal for cool-season grasses; late spring for warm-season types like Bermuda and Zoysia.
Does more seed make a thicker lawn?
Up to a point — over-seeding wastes seed and causes seedlings to compete. Stick close to the recommended rate for even coverage.