Grass Seed Calculator
Pounds of seed for new lawns and overseeding, by grass type.
Enter your values
Enter the lawn area in sq ft.
Choose one of: Tall fescue (6 lb/1000), Kentucky bluegrass (3 lb/1000), Perennial ryegrass (8 lb/1000), Bermuda (1.5 lb/1000), Zoysia (1 lb/1000).
Choose one of: New lawn, Overseeding.
Enter the bag size in lb.
Enter the cost per bag in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Seed needed
- 30 lb
- Bags to buy
- 2 x 20 lb
- Seed cost
- $120.00
- Starter fertiliser
- 5 units of 1,000 sq ft coverage
Working
- 15,000 / 1000 x 6 lb x 1 = 30 lb
Quick answer
Seeding rates differ by species: multiply your lawn area by the rate per 1,000 sq ft, and halve it for overseeding an existing lawn.
seed lb = area / 1000 x rate x (0.5 if overseeding)
At a glance
| What it does | Pounds of seed for new lawns and overseeding, by grass type. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Lawn area, Grass type, Job type, Bag size, Cost per bag |
| Main output | Seed needed |
| Formula | seed lb = area / 1000 x rate x (0.5 if overseeding) |
| Cost | Free — no sign-up, no download |
How to use the Grass Seed Calculator
- 1Measure the lawn area, subtracting beds, paths and the driveway.
- 2Choose the species you are sowing - rates vary by a factor of eight.
- 3Halve the rate when overseeding a thin but living lawn.
Inputs explained
- Lawn area(sq ft)
- Enter the lawn area in sq ft.
- Grass type
- Choose one of: Tall fescue (6 lb/1000), Kentucky bluegrass (3 lb/1000), Perennial ryegrass (8 lb/1000), Bermuda (1.5 lb/1000), Zoysia (1 lb/1000).
- Job type
- Choose one of: New lawn, Overseeding.
- Bag size(lb)
- Enter the bag size in lb.
- Cost per bag($)
- Enter the cost per bag in $.
Worked example
Using the values the calculator loads with:
Inputs
- Lawn area5000 sq ft
- Grass typeTall fescue (6 lb/1000)
- Job typeNew lawn
- Bag size20 lb
- Cost per bag60 $
Results
- Seed needed30 lb
- Bags to buy2 x 20 lb
- Seed cost$120.00
- Starter fertiliser5 units of 1,000 sq ft coverage
- 5,000 / 1000 x 6 lb x 1 = 30 lb
Frequently asked questions
Can I use more seed to get a thicker lawn?
No. Over-seeded grass competes with itself, produces weak seedlings and thins out within a season. Stick to the label rate.
When is the best time to seed?
Early autumn for cool-season grasses and late spring for warm-season grasses, when soil temperature suits germination.
What do I need to enter into the Grass Seed Calculator?
Just 5 values: lawn area, grass type, job type, bag size, cost per bag. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Grass Seed Calculator work out the answer?
Seeding rates differ by species: multiply your lawn area by the rate per 1,000 sq ft, and halve it for overseeding an existing lawn. It applies the formula seed lb = area / 1000 x rate x (0.5 if overseeding) and shows the working so you can check each step by hand.
Is the Grass Seed Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.