Grass Seed Calculator
Enter your lawn's size and grass type and get the pounds of seed to buy at University of Kentucky Extension's seeding rates, adjusted for your seed tag's pure live seed.
Rates marked PLS are pure live seed; the page converts them to pounds of bagged seed using your tag's purity and germination.
Seed to buy
12 lb of seed
2,000 ft² at 6 lb per 1,000 ft²
| Area | 2,000 ft² (0.046 acres) |
| Seeding rate | 6 lb per 1,000 ft² |
What this page cannot tell you
Which grass suits your yard, or rates for overseeding an existing lawn. The rates are University of Kentucky's for new lawns in Kentucky; other states' extension services publish their own. Seed blends list their own rate on the bag — use 'Rate from my seed bag' for those.
How to calculate how much grass seed you need
- Measure the lawn. Length × width, or the total square footage.
- Choose the grass. Kentucky bluegrass, tall fescue, perennial ryegrass, a bluegrass/ryegrass mix, bermudagrass, or your bag's own rate.
- Enter the seed tag figures. Purity and germination, to convert pure live seed rates into bagged pounds.
- Add a bag size. Optional, for the number of bags.
10 situations where a grass seed calculator helps
Seeding a new lawn
Buy the right amount for bare soil.
Comparing grass types
Tall fescue is seeded at three times the rate of bluegrass; see the difference in pounds.
Reading a seed tag
Turn purity and germination into how much bagged seed gives the PLS rate.
Buying in bulk
Bag counts for large areas.
Bluegrass with a little ryegrass
The mix rate for quicker cover.
Bermudagrass from seed
Rates for seeded cultivars.
Bare patches
Measure the patch and seed just that area.
Contractor bids
Material quantity for a lawn installation.
Budgeting
Pounds × price per pound.
Using a different rate
Choose 'rate from my seed bag' for blends.
Where the seeding rates come from
The rates are from University of Kentucky Cooperative Extension publication AGR-52, 'Selecting the Right Grass for Your Kentucky Lawn' (Gregg Munshaw and Trevor Shaddox, issued August 2019), for new lawns: Kentucky bluegrass 2 pounds of pure live seed per 1,000 ft²; turf-type tall fescue 6 pounds per 1,000 ft²; perennial ryegrass 4–6 pounds of pure live seed per 1,000 ft² when broadcast-seeded; bluegrass with about 15% perennial ryegrass by weight as about ¼ pound of ryegrass with 1½ pounds of bluegrass per 1,000 ft²; and seeded bermudagrass 1–2 pounds of pure live seed per 1,000 ft².
Pure live seed (PLS) is the share of a bag that is both the right seed and able to germinate: purity × germination from the seed tag. A PLS rate is divided by that fraction to get pounds of bagged seed. Rates AGR-52 gives as plain pounds are used as they are.
Limits: these are Kentucky's rates for new lawns. Overseeding an existing lawn usually uses less, and other states' extension services publish their own figures — use 'rate from my seed bag' for those or for blends. Which grass suits your yard is outside this page. Everything runs in your browser.
Sources
- University of Kentucky Extension — AGR-52 Selecting the Right Grass for Your Kentucky Lawn — New-lawn seeding rates per 1,000 ft²
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends on the grass: UK Extension gives 6 lb for tall fescue, 2 lb PLS for Kentucky bluegrass and 4–6 lb PLS for perennial ryegrass for new lawns.
How much seed for a 5,000 sq ft lawn?
At tall fescue's 6 lb per 1,000 ft², 30 pounds.
What is pure live seed?
The fraction of the bag that is viable seed of the species: purity × germination. A 2 lb PLS rate at 90% purity and 80% germination is 2.8 lb of bagged seed.
Is overseeding the same rate?
No — these rates are for new lawns. Check your seed bag or local extension for overseeding.
Can I mix tall fescue with ryegrass?
AGR-52 advises against mixing tall fescue with perennial ryegrass or fine fescue because of texture and growth differences.
Where do I find purity and germination?
On the seed analysis tag on the bag.
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