Grass Seed Calculator

Find out exactly how much grass seed your lawn needs. Pick from a database of 20 grass species with university-extension seeding rates, choose new lawn or overseeding, and get bag counts, spreader guidance, a watering schedule, and a full project cost — all calculated instantly in your browser. The same engine doubles as an overseeding calculator, a grass seed coverage calculator, a lawn seed calculator, and a grass seed rate calculator — four names for one tool.

Wondering how much grass seed do I need for 5000 sq ft? Example: a 5,000 sq ft new Tall Fescue lawn needs 40 lb of seed — 44 lb with a 10% waste buffer, which is 1 x 25-lb bag + 1 x 10-lb bag + 3 x 3-lb bags.

Scope note: this tool answers how much seed to buy and sow. For feeding new seed or seedlings, use our fertilizer calculator; for installed turf rolls instead of seed, use our sod calculator.

1 · Seed amount, bags & cost — lawn seeding cost calculator

Area → pounds of seed → bag rounding → project cost. Wondering how much does it cost to seed a lawn? Select Acres to use this as a grass seed per acre calculator and see how many pounds of grass seed per acre your lawn needs.

Grass species Project type

Lawn shape

Length (ft)

Width (ft)

Waste buffer: 10% Bag sizes available (lb) Seed price ($ per lb) Starter fertilizer ($) Straw ($ per bale, ~1 bale per 1,000 sq ft)

2 · Species database — new lawn seeding rate chart

New-lawn rates in lb per 1,000 sq ft, cross-checked against Purdue, Virginia Tech, and Cornell extension publications — read the table as a grass seed calculator per 1000 sq ft. Overseeding uses half the new-lawn rate, and the Germination column doubles as a grass seed germination time chart.

Species	New lawn (lb/1k ft²)	Overseed (lb/1k ft²)	Sun	Season	Germination	Notes
Kentucky Bluegrass	3.0	1.50	Full sun - light shade	Cool-season	14–30 days	Slow to germinate; spreads by rhizomes and self-repairs.
Perennial Ryegrass	6.0	3.00	Full sun	Cool-season	5–10 days	Fastest cool-season germination; often mixed with bluegrass.
Tall Fescue	8.0	4.00	Full sun - moderate shade	Cool-season	7–14 days	Deep roots; the toughest cool-season choice for heat and traffic.
Fine Fescue (Creeping Red)	4.0	2.00	Shade tolerant	Cool-season	7–14 days	Best pick for deep shade; low maintenance.
Chewings Fescue	4.0	2.00	Shade - part sun	Cool-season	7–14 days	Fine texture; common in shade mixes.
Hard Fescue	3.5	1.75	Shade - part sun	Cool-season	7–14 days	Very low maintenance; drought hardy.
Sheep Fescue	3.5	1.75	Full sun - part shade	Cool-season	7–14 days	Bunch grass for low-input lawns.
Annual Ryegrass	5.0	2.50	Full sun	Cool-season	5–10 days	Temporary nurse grass; dies out in summer heat.
Creeping Bentgrass	2.0	1.00	Full sun	Cool-season	5–10 days	Golf-course turf; needs close, frequent mowing.
Colonial Bentgrass	1.5	0.75	Full sun - light shade	Cool-season	5–10 days	Fine lawn turf for cool coastal climates.
Rough Bluegrass	5.0	2.50	Shade, moist soil	Cool-season	7–14 days	For wet shady spots; poor heat tolerance.
Bermudagrass (Common)	3.0	1.50	Full sun	Warm-season	10–30 days	Aggressive spreader; needs soil above 65 F.
Zoysia (Seeded)	2.0	1.00	Full sun - light shade	Warm-season	14–21 days	Dense and slow-growing; needs soil above 70 F.
Centipedegrass	1.5	0.75	Full sun - light shade	Warm-season	14–28 days	Low-maintenance southern lawns.
Bahiagrass	9.0	4.50	Full sun	Warm-season	14–21 days	Coarse pasture-type turf; extremely drought tough.
Buffalograss	4.0	2.00	Full sun	Warm-season	14–21 days	Native prairie grass; minimal water once established.
Seashore Paspalum	1.0	0.50	Full sun	Warm-season	7–14 days	Salt-tolerant; for coastal lawns.
White Clover (Micro)	2.0	1.00	Full sun - part shade	Cool-season	7–10 days	Lawn alternative; fixes nitrogen and stays green.
Tall Fescue Blend	7.0	3.50	Full sun - shade	Cool-season	7–14 days	Commercial blend of fescue cultivars.
Sun & Shade Mix	6.0	3.00	Sun - shade	Cool-season	7–14 days	Bluegrass / ryegrass / fine fescue mix for mixed light.

Headline rates from the chart: the kentucky bluegrass seeding rate per 1000 sq ft is 3 lb, the tall fescue seeding rate per 1000 sq ft is 8 lb, and the bermuda grass seed rate per 1000 sq ft is 3 lb for a new lawn — halve each for overseeding.

3 · Spreader guide — broadcast spreader vs drop spreader grass seed

Use a broadcast (rotary) spreader for areas over about 1,000 sq ft — fastest coverage. Use a drop spreader for precise edges, narrow strips, and windy days. Apply half the seed walking north-south and the other half east-west so the two passes cross.

How to calibrate a spreader for grass seed

Weigh the exact seed for a test strip, spread it at the bag's suggested dial setting, and adjust until it matches.

Test strip area (sq ft)

Weigh out: —

of the selected species at the selected project rate, then spread the strip.

Mark the test strip and weigh the seed amount shown above.
Set the spreader dial to the setting printed on the seed bag.
Spread the strip. Seed runs out early? Close the dial one notch. Seed left over? Open it one notch.
Repeat until the weighed amount covers the strip exactly — then seed the whole lawn.

4 · Watering schedule — grass seed watering schedule first two weeks

Generated for the species selected above.

Frequently asked questions

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

It depends on the species. Typical new-lawn rates per 1,000 sq ft are: Tall Fescue 8 lb, Perennial Ryegrass 6 lb, Kentucky Bluegrass 3 lb, Bermudagrass 3 lb, Fine Fescue 4 lb, and Centipedegrass 1.5 lb. Overseeding uses half of the new-lawn rate. The formula is (area / 1,000) x rate. Example: a 5,000 sq ft new Tall Fescue lawn needs 5 x 8 = 40 lb of seed.

How much grass seed per square foot?

Divide the per-1,000-sq-ft rate by 1,000. Tall Fescue at 8 lb per 1,000 sq ft is 0.008 lb per square foot - about 3.6 grams. For whole lawns it is easier to work per 1,000 sq ft: (area / 1,000) x rate gives pounds directly.

What is the difference between new lawn seeding and overseeding rates?

Overseeding spreads seed over existing turf to thicken it, so it uses half of the new-lawn rate. Patch repair of bare spots uses about three quarters. Example on a 5,000 sq ft Tall Fescue lawn: new lawn = 40 lb, overseeding = 20 lb (22 lb with a 10 percent waste buffer -> 1 x 10-lb bag + 4 x 3-lb bags), patch repair = 30 lb (33 lb with buffer).

How much grass seed for overseeding?

Half of the new-lawn rate per 1,000 sq ft. Tall Fescue at 8 lb becomes 4 lb; a 5,000 sq ft overseeding job needs 5 x 4 = 20 lb, or 22 lb with the 10% waste buffer. Select the Overseeding button above and this page acts as your overseeding calculator.

How many bags of grass seed do I need?

Divide total pounds by the bag size and round up to whole bags. Seed is sold in 3, 5, 10, 20, 25, and 50 lb bags, and the calculator picks the combination with the least leftover seed. Example: 44 lb needed -> 1 x 25-lb bag + 1 x 10-lb bag + 3 x 3-lb bags (44 lb total, exact - no leftover seed). Use this page as a grass seed bag coverage calculator: enter your area and species above and it converts pounds into exact bag combinations.

Should I buy extra seed beyond the calculated amount?

Yes. A 10% buffer is the standard default - it covers seed lost to wind, birds, and uneven spreading, plus touch-up reseeding of thin spots. Adjust 0-30% based on your spreader and conditions. Example: 40 lb x 1.10 = 44 lb to buy.

Should I use a broadcast spreader or a drop spreader for grass seed?

Use a broadcast (rotary) spreader for areas over about 1,000 sq ft - it is the fastest way to cover large areas. Use a drop spreader for precise edges, narrow strips, and windy days when a broadcast spreader would scatter seed. For even coverage, apply half the seed walking north-south and the other half walking east-west.

How do I calibrate my spreader for grass seed?

Mark a 1,000 sq ft test strip and weigh the exact seed for it - for example 8 lb of Tall Fescue. Set the dial to the setting printed on the seed bag (Scotts, Pennington, and Jonathan Green list settings for popular spreader models), then spread the strip. If seed runs out early, close the dial a notch; if seed is left over, open it. Re-test until the weighed amount covers the strip exactly.

How long does grass seed take to germinate?

Perennial Ryegrass 5-10 days; Tall and Fine Fescues 7-14 days; Kentucky Bluegrass 14-30 days; Bermudagrass 10-30 days; Zoysia 14-21 days; Centipedegrass 14-28 days. Warm-season grasses need soil temperatures above 65 F to start. Consistent moisture is the biggest factor you control.

How often to water new grass seed?

Keep the seedbed consistently moist, never soaked and never dry. Water lightly 2-3 times daily for the first two weeks, then once daily until the first mowing. After establishment, switch to deep watering of about 1 inch per week. Seed that dries out during germination dies.

Do I need starter fertilizer or straw over new grass seed?

A phosphorus-rich starter fertilizer applied at seeding time promotes root growth; avoid high-nitrogen fertilizer until the lawn is established. Cover broadcast seed with weed-free straw at 50-90 lb per 1,000 sq ft (about 1 bale per 1,000 sq ft) to hold moisture and stop erosion. Example budget for a 5,000 sq ft lawn: $154.00 seed + $25.00 starter fertilizer + $40.00 straw (5 bales x $8) = $219.00 total.

When is the best time to plant grass seed?

Cool-season grasses (fescue, bluegrass, ryegrass) establish best in early fall when soil is 50-65 F - warm enough to germinate, cool enough to limit heat stress and weeds. Warm-season grasses (bermuda, zoysia, centipede) go down in late spring once soil stays above 65 F. Spring seeding of cool-season grass works but fights more weeds and summer heat. That is the full answer to when to plant grass seed fall vs spring: fall for cool-season grasses, late spring for warm-season.