Grass Seed Calculator – Pounds of Seed per 1,000 Sq Ft

How to use the grass seed calculator

Calculate grass seed

Rates are for pure live seed per 1,000 sq ft. Coated seed weighs more per seed, so follow the bag label if it gives a different rate. Estimates only.

Choose the shape of your lawn: rectangle, circle or triangle.
Enter the length and width (or diameter) in feet. For several separate areas, run the calculator for each and add them together.
Pick your grass type and whether this is a new lawn or overseeding an existing one. Overseeding uses about half the new-lawn rate.
Read off the seed needed in pounds and the number of bags in common sizes.

Seeding rates by grass type

Grass type	New lawn (lb per 1,000 sq ft)	Overseeding (lb per 1,000 sq ft)
Kentucky bluegrass	3	1.5
Perennial ryegrass	9	4.5
Tall fescue	8	4
Fine fescue	5	2.5
Bermudagrass (hulled)	2	1
Sun and shade mix	6	3

Rates differ because seed sizes differ. A pound of Kentucky bluegrass holds over a million tiny seeds, while a pound of ryegrass holds a fraction of that, so bluegrass is spread far thinner by weight. Always check the rate printed on your bag as well: coated seed is heavier per seed and some labels adjust for it.

New lawn or overseeding?

A new lawn starts from bare soil, so it gets the full rate and needs the soil prepared: levelled, raked and firmed so seed touches soil everywhere. Overseeding thickens an existing lawn: mow short, rake out thatch so seed reaches the ground, and spread at half rate. Autumn is the best season for both in cool-season lawns, because warm soil germinates seed fast while weeds are slowing down.

Tips for a lawn that actually takes

Seed-to-soil contact is everything. Seed sitting on thatch or dry fluff dries out and dies; rake, roll or cover lightly with a quarter inch of compost or peat.
Water little and often until germination: the seedbed should never dry out in the first two weeks.
Spread half the seed walking one way and half walking across it, so coverage is even.
Hold off on weed-and-feed products around seeding: most prevent grass seed from germinating too.

Frequently Asked Questions

How much grass seed do I need per 1,000 sq ft?

It depends on the grass: about 3 lb for Kentucky bluegrass, 8 lb for tall fescue, 9 lb for perennial ryegrass, 5 lb for fine fescue and 2 lb for bermudagrass. Halve those rates for overseeding.

How much seed do I need for an acre?

An acre is 43,560 sq ft. At tall fescue's 8 lb per 1,000 sq ft, a new lawn takes about 350 lb of seed; Kentucky bluegrass takes about 130 lb. The calculator gives exact figures for your own area.

How much area does a 25 lb bag of seed cover?

At new-lawn rates, about 3,100 sq ft of tall fescue, 2,800 sq ft of perennial ryegrass or 8,300 sq ft of Kentucky bluegrass. Overseeding roughly doubles the coverage.

Can you put down too much grass seed?

Yes. Overcrowded seedlings compete for water and light, grow weakly and invite fungus. Stick close to the recommended rate; the extra allowance in this calculator is for edges and thin spots, not for doubling up.

How long does grass seed take to germinate?

Perennial ryegrass is fastest at about 5 to 10 days, tall fescue 7 to 14 days, and Kentucky bluegrass the slowest at 14 to 30 days. Keep the seedbed damp the whole time.

When is the best time to plant grass seed?

Early autumn for cool-season grasses: warm soil, cool air and fewer weeds. Spring is second best, before summer heat. Bermudagrass and other warm-season grasses go down in late spring into early summer.

Should I cover grass seed after spreading?

A light covering, about a quarter inch of compost, topsoil or peat, holds moisture and hides seed from birds. It is optional on overseeding but worth it on bare soil.

How should I store leftover grass seed?

Cool, dry and sealed, away from mice and moisture. Seed keeps most of its germination for 2 to 3 years; older seed can still be used at a slightly higher rate.