Grass Seed Calculator
Pounds of seed, matched to your grass and your job. Free, instant, and private — everything runs on your device.
Quality seed runs $3–$8/lb
Your grass seed estimate
- Lawn area
- 2,400 sq ft
- Seeding rate
- 6 lb / 1,000 sq ft
- Buy (5-lb bags)
- 3
- Estimated cost
- $72
Overseeding an existing lawn uses about half the new-lawn rate. Rates vary by grass type — the picker sets a typical value; always check your seed bag, which prints the exact rate for that blend.
Buy grass seed by feel and you'll either sow it so thin the weeds win, or so thick the seedlings choke each other out. The right amount is a rate — pounds per thousand square feet — and it changes with two things: your grass type and whether you're starting a bare lawn or thickening an existing one. This calculator handles both. Enter your lawn's size, pick your grass, choose new-lawn or overseed, and it returns the pounds to buy.
Overseeding uses roughly half the new-lawn rate, and the seeding rate itself swings from about 2 lb per thousand for Bermuda up to 8 for fine fescue. Getting it right is the difference between a lawn that fills in evenly and one you're patching all season.
How it works
No black box — this is the exact math the calculator runs.
- Lawn area = length × width, in square feet.
- New-lawn rate is set by grass type (e.g. tall fescue ≈ 6, Kentucky bluegrass ≈ 3, fine fescue ≈ 8 lb per 1,000 sq ft).
- Overseeding uses half the new-lawn rate.
- Pounds = (area ÷ 1,000) × rate.
- Bags round up to whole 5-lb bags; cost = pounds × your price per pound.
Last reviewed July 24, 2026 · Garden & Landscaping
Frequently asked questions
How much grass seed do I need for 5,000 square feet?
For a new tall-fescue lawn at 6 lb per 1,000 sq ft, that's 30 pounds. Overseeding the same area needs about 15 pounds. Bermuda would need far less; fine fescue more — the grass type genuinely changes the answer.
What is the difference between seeding and overseeding rates?
A new lawn covers bare soil, so it needs the full rate for complete coverage. Overseeding drops seed into existing turf to thicken it, so it uses about half. Using the full rate to overseed just wastes seed to competition from the established grass.
Can I use too much grass seed?
Yes. Over-seeding forces seedlings to compete for water, light, and nutrients, producing thin, weak grass prone to disease. More seed is not a faster lawn — the correct rate germinates into the densest turf.
When is the best time to plant grass seed?
Early fall is ideal for cool-season grasses (fescue, bluegrass, rye) — warm soil, cool air, fewer weeds. Late spring to early summer suits warm-season grasses like Bermuda. Seeding in the wrong season is the most common reason a new lawn fails.