Grass Seed Calculator: How Much Grass Seed Do I Need?
When calculating how much grass seed you need, the first step is finding your lawn’s square footage.
The condition of your lawn also affects the amount of seed it needs.
You won’t need as much seed if you’re overseeding (or seeding over an existing lawn).
More seed is required to grow a brand-new lawn.
Wondering how much grass seed you need for your lawn? It all depends on the size of your yard and the current condition of your grass. Whether you’re overseeding your existing lawn or starting one from scratch, here’s how to calculate the right amount of grass seed for your needs.
How Much Grass Seed Do You Need for Your Lawn?
The amount of grass seed you need depends on whether you’re seeding over an existing lawn (also known as overseeding) or seeding a new lawn. Overseeding requires two to five pounds of grass seed per 1,000 square feet of lawn, while new lawn seeding requires four to eight pounds per 1,000 square feet.
Here’s how much grass seed you’ll need based on the size and condition of your lawn:
| Lawn Size (in Square Feet) | Grass Seed Needed for Overseeding (in Pounds) | Grass Seed Needed for New Lawn Seeding (in Pounds) |
|---|---|---|
| 1,000 | 2–5 | 4–8 |
| 2,500 | 5–13 | 10–20 |
| 5,000 | 10–25 | 20–40 |
| 7,500 | 15–38 | 30–60 |
| 10,000 | 20–50 | 40–80 |
| 15,000 | 30–76 | 60–120 |
| 20,000 | 40–100 | 80–160 |
| 30,000 | 60–152 | 120–240 |
| 40,000 | 80–200 | 160–320 |
| 50,000 | 100–250 | 200–400 |
| 75,000 | 150–375 | 300–600 |
Calculating the Right Amount of Grass Seed
To calculate how much grass seed you should buy, you’ll first need the square footage of your lawn.
You’ll also need to know how many pounds of seed are required to seed 1,000 square feet. That figure may be listed on the product packaging, but if it’s provided in a different format (say, pounds per 4,000 square feet), you can do some quick math to convert it to pounds per 1,000 square feet.
When you have those numbers, you can use the following formula to determine your grass seed needs:
Pounds of Grass Seed Needed = (Lawn Size in Square Feet / 1,000) x Pounds of Seed Required per 1,000 Square Feet
How to Measure Your Lawn for Grass Seed
You’ll need to measure the square footage of your lawn to figure out how much grass seed to order. The process for doing this will depend on the layout of your yard.
How to Measure a Rectangular Lawn for Grass Seed
Follow these steps to get the square footage of a square or rectangular lawn:
Measure the length.
Measure the width.
Multiply the numbers to get the square footage.
You can use this same process if there are recessed or protruding areas of your lawn. For example, if you have a rectangular shed in the middle of your yard, you can calculate its square footage and subtract that from the lawn’s overall square footage.
How to Measure an Irregular-Shaped Lawn for Grass Seed
If your lawn includes curved edges, here’s how to get a rough idea of its area:
To estimate the length, measure the longest part of the lawn.
To estimate the width, measure the width in several different areas and come up with an average.
Multiply the length and width to get a ballpark idea of the square footage.
Who to Hire to Seed Your Lawn
Calculating the right amount of grass seed is fairly simple, but the actual process of seeding your lawn is more challenging. To grow a healthy lawn, you don’t just need to know how much seed to use. You should also understand how and when to apply it and how to nurture your lawn until the new grass comes in. For the best results, consider hiring a local lawn seeding pro instead of tackling this job yourself.
Frequently Asked Questions
Yes, you should water your grass after seeding it. During the first couple of weeks after laying the seed, you should water the lawn two or three times per day for 10 to 15 minutes each session. After that, you can switch to 20- or 30-minute watering sessions every other day.
The best time to plant grass seed will depend on your location and the type of grass. But generally speaking, you should try to plant warm-season grass (like St. Augustine grass) between late spring and early summer. Meanwhile, it’s better to plant cool-season grasses (such as tall fescue) from late summer to early fall.
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