Lawn Seed Calculator
Determine the exact weight of grass seed required for your lawn project. Whether establishing a new lawn on bare dirt or overseeding an established yard in the autumn, this tool matches university seeding rates across all major cool-season and warm-season turfgrass varieties.
Total square footage needing grass seed
Seeding density varies dramatically by seed size and germination habit
Used only if "Custom Application Rate" is selected above
Total pounds of grass seed to purchase
How to Use This Calculator
- Measure your lawn area in square feet.
- Select your turfgrass species and whether you are sowing a new lawn or overseeding.
- Review the total seed weight in pounds and kilograms.
- Buy high-quality certified seed with 0.0% weed seed and high germination ratings.
Formula & Calculation Methodology
Sowing rates vary based on seed particle size and count per pound. Kentucky Bluegrass has over 1,300,000 seeds per pound and requires only 2.5 lbs/1,000 sq ft, whereas Tall Fescue has ~225,000 seeds per pound and requires 6 to 8 lbs.
Worked Example
3,000 sq ft new lawn with Tall Fescue (7 lbs / 1,000 sq ft)
5,000 sq ft overseeding with Kentucky Bluegrass (1.25 lbs / 1,000 sq ft)
Frequently Asked Questions
What is the difference in seed rate between a new lawn and overseeding?↓
A new bare-ground lawn requires a higher seed density (e.g. 6–8 lbs/1,000 sq ft for fescue) to achieve thick coverage and outcompete weeds. Overseeding existing turf requires about half that rate (3–4 lbs/1,000 sq ft) to fill in thin patches without overcrowding.
What does "coated seed" mean on grass seed bags?↓
Many retail brands coat seeds with water-absorbent starch and fungicide. While coating improves moisture retention, the coating makes up 30% to 50% of the bag’s total weight, meaning a 50 lb bag may only contain 25–35 lbs of actual raw seed.
When is the best time of year to seed grass?↓
For cool-season grasses (Fescue, Bluegrass, Ryegrass), late summer to early autumn (late August through September) is ideal because warm soil and cool air promote rapid germination with minimal weed competition. Warm-season grasses (Bermuda, Zoysia) should be seeded in late spring.
What is a limitation of buying cheap contractor grass seed?↓
Economy seed blends often contain high percentages of annual ryegrass (which dies after one season) or undesirable "other crop" and weed seeds (such as coarse orchardgrass or Poa trivialis) that permanently contaminate lawns.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.