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Grass Seed Calculator
Enter your lawn area and choose a grass type to find how many pounds of seed to buy. Rates differ for starting a new lawn and for overseeding an existing one, and you can enter your own rate from the seed bag.
- Rate used
- 8 lb per 1,000 sq ft
- Seed cost
- $160.00
Saved setups
Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.
Your recent calculations
Results you calculate here are kept on this device so you can come back to them.
Formula
How to use it
- Enter the lawn area, in square feet, acres or square meters.
- Choose the grass type.
- Choose a new lawn or overseeding.
- Enter the price per pound for a cost estimate.
Worked examples
A new 5,000 sq ft tall fescue lawn at $4 a pound
- Rate used
- 8 lb per 1,000 sq ft
- Seed needed
- 40 lb
- Seed cost
- $160.00
Overseeding 8,000 sq ft of Kentucky bluegrass at $7 a pound
- Rate used
- 1.5 lb per 1,000 sq ft
- Seed needed
- 12 lb
- Seed cost
- $84.00
Rates used
In pounds per 1,000 sq ft, new lawn then overseeding: tall fescue 8 and 4; Kentucky bluegrass 3 and 1.5; perennial ryegrass 8 and 4; fine fescue 5 and 2.5; hulled bermudagrass 2 and 1. These sit within the ranges commonly recommended by seed suppliers and university extension services.
Rates vary with seed size and coating — coated seed needs a higher rate by weight — so the label on your bag takes priority. Choose “Custom rate” to enter it.
Getting it to grow
More seed is not better: overcrowded seedlings compete and are prone to disease. Spread half the seed walking one direction and half at right angles for even coverage. Cool-season grasses (fescue, bluegrass, ryegrass) establish best in early fall; warm-season grasses such as bermuda are seeded in late spring. Keep the surface moist until the grass is established.
To measure your lawn, split it into rectangles and triangles and add the areas. One acre is 43,560 sq ft.
Questions people ask
How much grass seed do I need for 5,000 square feet?
For a new tall fescue lawn at 8 lb per 1,000 sq ft, 40 lb. For Kentucky bluegrass at 3 lb per 1,000 sq ft, 15 lb. Overseeding takes about half as much.
How much grass seed per acre?
An acre is 43.56 thousand square feet, so about 350 lb of tall fescue or 130 lb of Kentucky bluegrass for a new lawn at the rates used here.
How much seed do I need to overseed?
About half the new-lawn rate: roughly 4 lb per 1,000 sq ft for tall fescue or ryegrass and 1.5 lb for Kentucky bluegrass.