Grass Seed Calculator

Pounds of grass seed for your lawn by grass type, for a new lawn or overseeding, with bags needed.

Seed needed = area ÷ 1,000 × seeding rate. A 5,000 sq ft new tall fescue lawn at 7 lb per 1,000 sq ft needs 35 lb of seed; overseeding the same lawn at 4 lb needs 20 lb.

Free, runs in your browser. Nothing you enter is uploaded.

How to use it

Enter the lawn area in square feet, square metres or acres.
Choose your grass type and whether it is a new lawn or overseeding.
Read the pounds of seed and bags to buy.

What you enter

Lawn area
Grass type
New lawn or overseeding
Bag size

What you get

Pounds and kilograms of seed
Seeding rate
Bags

Formula

Seed (lb) = area (sq ft) / 1,000 × rate (lb per 1,000 sq ft)

Worked example

Input: 5,000 sq ft new tall fescue lawn

Result: 35 lb of seed (5 × 7 lb bags)

Spread half in one direction and half crosswise for even cover.

Questions

How much grass seed do I need per 1,000 square feet?

It depends on seed size: about 2–3 lb for Kentucky bluegrass, 6–8 lb for tall fescue, 7–9 lb for perennial ryegrass and 1–2 lb for hulled bermuda for a new lawn. Overseeding uses roughly half.

Can I put down too much grass seed?

Yes. Overcrowded seedlings compete for water and light and are more prone to disease, so stick to the label rate.

When is the best time to seed a lawn?

Early fall for cool-season grasses (bluegrass, fescue, ryegrass) and late spring to early summer for warm-season grasses (bermuda, zoysia, centipede).

How do I measure my lawn?

Break it into rectangles and circles, multiply length × width for each and add them. Leave out the house, driveway and beds.

References

Penn State Extension (2023) Lawn Establishment: Seeding and Sodding.

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All free tools · By Dr. Zubair Khalid, DVM, MS, PhD.