Grass Seed Calculator — Pounds per Lawn

Pounds of seed for a lawn, at a rate one of four university extension services publishes.

Showing US units

Seed to buy EXAMPLEat least 21.8 lb of seed of turf-type tall fescue, labeled 92% pure seed and 80% germination, no other grass on the label

An answer marked EXAMPLE is worked out from the page’s sample values. Type your own over the values marked SAMPLE to make it yours.

sq ftSAMPLE

The area of the ground to be seeded, measured out to its edges, with beds, the drive and anything else that is not grass taken out. Length times width.

Not every publisher prints a rate for every grass, and where one does not, this says so and names who does.

Four university extension services, four different answers for the same grass. They are written for different climates — pick the one nearest you, and the answer will say whose it is.

Starts at Penn State — the first of the four extension services in the list, not a recommendation: they write for different climates, so the one nearest the lawn is the one to pick.

Overseeding usually takes less seed. Of the four extension services here only Penn State prints an overseeding rate, and only for perennial ryegrass; for everything else what NC State publishes is a rule, and the answer will say so.

%SAMPLE

The percentage of the bag’s weight that the seed label gives for this grass, often headed pure seed or purity. If the label lists several varieties of this grass, add their percentages. The sample, 92, is the pure seed in Penn State’s own worked example of pure live seed; copy the figure from the label of the bag to be bought.

%SAMPLE

The germination percentage the seed label prints. Penn State’s rates count only seed that germinates, so it changes the weight to buy at Penn State’s rate. If the label gives one for each variety of this grass, enter the lowest: it never gives less seed than an average of them would. The sample, 80, is the germination in the same worked example.

0%

Starts at 0% — this calculator’s own starting point, not a published figure. None of the extension services or seed companies this calculator cites prints an over-order allowance for seed, so the calculator adds none rather than invent one. Change it to how much seed to keep back for patching a thin spot.

Seed to buy EXAMPLEat least 21.8 lb of seed of turf-type tall fescue, labeled 92% pure seed and 80% germination, no other grass on the label

The weight is of seed as bagged: the pure live seed the lawn needs, divided by the seed label’s pure-seed percentage for this grass times its germination percentage — Penn State’s pure live seed. Source

Pure live seed the lawn needs 16.0 lb

Seeding rate used, per 1,000 square feet — from Penn State Source 8.0 lb

The lighter end of the same recommendation, per 1,000 square feet Source 6.0 lb

A 2,000 square foot lawn, on the grass, rate publisher and job chosen above.

Pure live seed the job needs16.0 lb
Pure live seed with 0% added for waste16.0 lb
As bagged, at 92% pure seed × 80% germinationat least 21.8 lb

Where the publisher prints a range, the order is worked out from its heavier end, because running short leaves bare ground and bare ground is where the weeds get in first; the lighter end is given with it.

Not counted in these quantities: starter fertilizer; straw or other mulch to cover a new seeding.

The seed is ordered at the heavier end of the published seeding rate — this calculator’s own choice, not a publisher’s: so a thin patch is less likely; the lighter end is stated with it.

Ground seeded2,000 sq ft

  • For tall fescue the published new-lawn rates are: Penn State 6 to 8, Purdue and Illinois 6 to 9, Rutgers 4 to 6, NC State 6 — all in pounds per 1,000 square feet. They are written for different climates and different soils, and this page does not average them. Switching the service chosen above changes the answer, and that is the honest state of the guidance rather than a fault in it. Source
  • Penn State counts its rates as pure live seed: ‘To calculate PLS, the percentage of pure seed of a cultivar is multiplied by the percent germination, and the product is divided by 100.’ Both percentages are on the seed label, and the weight of seed to buy follows Penn State’s next step: ‘To determine how much seed to plant, divide 100 by the percentage PLS’. Coated seed is tested with the coating counted as inert matter, so the label’s percentages already leave a coating out. Source
  • The answer is the weight of seed to buy, not a number of bags: the one seed bag on record here whose page lists what is in it, Scotts Turf Builder Sun & Shade Mix, holds five grasses blended with lawn food and a soil improver, so its weight is not a weight of any one grass. Source
  • The seed stays in pounds whichever way the lawn is measured. A US shop sells it by the pound, in bags of several weights, so restating the order in kilograms would hand over a number nobody at the counter is quoting from — the unit switch changes how the lawn is measured, not what the shop sells.
  • Purdue and Illinois print their tall fescue rate twice in the same row of their table, and the two columns do not agree at the heavy end. The per-1,000-square-foot column says 6.0-9.0; the per-acre column says 261-348. An acre is 43,560 square feet, so 6.0 pounds per 1,000 square feet is 261 pounds per acre, as printed, but 9.0 would be 392, and 348 pounds per acre is 8.0 pounds per 1,000 square feet. Both columns are transcribed as the publication prints them, and the publication does not say which is right. ConcreteTally takes Purdue and Illinois’ heavy end as 9, from the per-1,000-square-foot column: it is in the unit the grass seed calculator works in, and it is the heavier of the two, so it cannot leave a lawn short of seed. Read from the per-acre column instead, Purdue and Illinois’ rate would be 8, one-ninth less seed. Source

The printed list carries the area, the rate, whose rate it is, and the weight of seed to buy.

Grass Seed Calculator — Pounds per Lawn

ConcreteTally

EXAMPLE — not a measured job. Every quantity below is worked out from this page’s sample measurements. Enter the real measurements and print it again before anyone orders from it.

Job / customer
Deliver to

Pure live seed the lawn needs: 16.0 lb

Seeding rate used, per 1,000 square feet — from Penn State: 8.0 lb [2]

The lighter end of the same recommendation, per 1,000 square feet: 6.0 lb [2]

What to buy

MaterialBuyWhich isLeft over
Grass seedat least 21.8 lb of seed of turf-type tall fescue, labeled 92% pure seed and 80% germination, no other grass on the label——
The weight is of seed as bagged: the pure live seed the lawn needs, divided by the seed label’s pure-seed percentage for this grass times its germination percentage — Penn State’s pure live seed.
This calculator’s own choicesThe seed is ordered at the heavier end of the published seeding rate — this calculator’s own choice, not a publisher’s: so a thin patch is less likely; the lighter end is stated with it.

Not counted in these quantities: starter fertilizer; straw or other mulch to cover a new seeding.

The rate on this sheet belongs to the university extension service named on it. It is that service’s figure, not a consensus figure. The weight to buy is of seed as bagged, for a bag whose label prints the figures on the line; a bag holds only the share of its weight that its seed label gives for that grass, and for a pure-live-seed rate only the part of that share the label says will germinate. It is a weight, not a count of bags: no bag on record here holds one grass alone.

Worked out from

Lawn area to seedThe area of the ground to be seeded, measured out to its edges, with beds, the drive and anything else that is not grass taken out.2000 sq ft (sample)
Which grass?Tall fescue
Whose seeding rate?Penn State — Mid-Atlantic and Northeast
New lawn, or seeding into one that is already there?A new lawn, from bare ground
Pure seed on the label92% (sample)
Germination on the label80% (sample)
Pure live seed needed16.0 lb
Extra to order over the published rate — Grass seednone — this calculator’s own starting point, not a published figure. None of the extension services or seed companies this calculator cites prints an over-order allowance for seed, so the calculator adds none rather than invent one.
As bagged, at 92% pure seed × 80% germinationat least 21.8 lb

Estimates only — check quantities before you buy. Confirm with your local garden center or your state extension service before ordering.

Where these figures come from

A number in brackets after a figure on this sheet is its entry in this list.

  1. Purdue University Extension and University of Illinois Extension seeding rates for lawns (AY-3-W 'Establishing Turfgrass Areas From Seed', page 2, Table 2 'Recommended seeding rates for lawns in Indiana and Illinois') — Purdue University Extension and University of Illinois Extension, University extension service. Effective from May 2006. The publication is marked as revised 5/2006; no day of month is printed. Authors: Reicher, Bigelow and Patton (Purdue), Voigt (Illinois). It is the second oldest of the four rate tables used here - Rutgers’ fact sheet, dated February 2004, is older - and it is recorded as dated rather than quietly refreshed. Retrieved October 11, 2026.
  2. Penn State Extension suggested seed mixtures and seeding rates for Pennsylvania lawns ('Lawn Establishment', Table 1 'Some suggested seed mixtures for home lawns, parks, grounds, and commercial properties in Pennsylvania': the single-species rows for sunny, well-drained soils, and the fine fescue row for partially shaded areas); Penn State Extension overseeding and renovation rate for perennial ryegrass ('Lawn Establishment', Table 1, the row headed 'Overseeding or renovation of lawns'); Penn State — how much of a bag counts against a seeding rate: pure live seed ('Lawn Establishment', section 'Seed Labels and Quality' — the list of what a label shows and the paragraphs on seed purity and pure live seed) — Penn State Extension, The Pennsylvania State University, University extension service. Effective from September 19, 2025. Retrieved October 11, 2026.
  3. Rutgers NJAES Cooperative Extension seeding rates by species (Fact sheet FS584 'Seeding Your Lawn', the per-species subsections for Kentucky bluegrass, tall fescues, fine fescues and perennial ryegrass) — Rutgers, The State University of New Jersey, New Jersey Agricultural Experiment Station, University extension service. Effective from February 2004. Dated February 2004 on the fact sheet; no day is printed. The site footer carries a current copyright year, which is a site-wide automatic notice and not a revision date for this text, so it is not used here. Retrieved October 11, 2026.
  4. NC State Extension planting dates and seeding rates for cool- and warm-season lawn grasses ('Carolina Lawns: A Guide to Maintaining Quality Turf in the Landscape' (AG-69), the cool-season and warm-season grass sections and Tables 2a, 2b and 2c); NC State — a seed coating calls for a higher seeding rate ('Carolina Lawns' (AG-69), the bermudagrass paragraph under the warm-season grasses) — NC State Extension, North Carolina State University, University extension service. Effective from July 2, 2021. Retrieved October 11, 2026.
  5. NC State Extension rule for reducing the seeding rate when seeding into existing grass ('Carolina Lawns' (AG-69), the paragraph on seeding rates immediately following the establishment tables) — NC State Extension, North Carolina State University, University extension service. Effective from July 2, 2021. Retrieved September 5, 2026.
  6. Iowa State University Extension on competition from established turf when overseeding ('Overseeding a Lawn', Yard and Garden how-to guide, preparation section) — Iowa State University Extension and Outreach, University extension service. Effective from August 2024. The page shows 'Last reviewed: August 2024'; no day is printed. Retrieved September 5, 2026.
  7. Scotts Turf Builder Sun & Shade Mix bag size and coverage claim (Product page for the 5.6 lb size, the 'how much do I need' question and the coverage specification block, the opening description and the 'Product Information' block) — The Scotts Company LLC (Scotts Miracle-Gro), Manufacturer or grower specification. Effective from 2026. The product page carries no publication or revision date. The year recorded is the year of retrieval, at year precision, so no month or day is shown that the publisher did not print. Retrieved October 11, 2026.
  8. Federal seed testing rule — a coating is counted with the inert matter (7 CFR 201.51b 'Purity procedures for coated seed', paragraphs (b) and (f)) — U.S. Department of Agriculture, Agricultural Marketing Service — Code of Federal Regulations, Title 7, Part 201 (Federal Seed Act regulations), via the eCFR, Government publication. Effective from December 14, 1994. The section’s own source note reads '[59 FR 64499, Dec. 14, 1994]'. Retrieved October 11, 2026.

This list, with a link to each document: concretetally.com/grass-seed-calculator/#sources-heading

Every table ConcreteTally reads, with its dates: concretetally.com/sources

Check the seed label on the bag in your hand against the amount on this sheet.

Where these figures come from

Every table ConcreteTally reads, with its dates: all sources.