Grass seed calculator
Work out how much seed to buy from your lawn area, grass type and task. Start with a default rate, or use the rate on your seed label.
How much grass seed do you need?
Quantity planning only. Grass choice, timing and seedbed condition still matter.
A 25 lb bag would cover the estimated range with some margin, if that size is available.
Check species, cultivar or mix, and seeding-rate guidance.
Start with the grass-specific rate.
These defaults are starting points for the calculator. The label wins. A mixture, coated seed, specialty cultivar, or regional recommendation may use a different rate.
| Grass | New lawn | Overseed | Seeding rate |
|---|---|---|---|
| Tall fescue | 6 to 8 lb | 4 lb | Default until the seed label gives a more specific rate. |
| Kentucky bluegrass | 2 to 3 lb | 1 to 1.5 lb | Default for KBG establishment and overseeding. |
| Fine fescue | 3 to 6 lb | 2 to 4 lb | Broad range because the fine-fescue group contains different species. |
Area × seeding rate gives you the starting quantity.
Seed quantity equals lawn area multiplied by the seeding rate for the grass and task. A 3,000 square foot lawn at 6 pounds per 1,000 square feet needs 18 pounds of seed. At 8 pounds per 1,000 square feet, the same lawn needs 24 pounds.
The calculator uses a range because seed recommendations are not always one exact national number. Cultivar, seed mixture, region, site condition, and label directions can change the useful rate.
The label may be more specific about the mixture, coating, cultivar or region. Enter its range directly when it is.
Measure the lawn, not the lot.
Exclude the house, driveway, patio, beds, pool, and other non-turf areas. For a mostly rectangular lawn, multiply length by width for each section and add the sections together. For irregular shapes, split the lawn into smaller rectangles or approximate pieces rather than measuring the entire property boundary.
60 ft × 40 ft = 2,400 sq ft.
Front + side + back lawn, excluding hardscape.
The calculator converts acres automatically.
Living turf usually needs less seed.
A bare seedbed relies on new seedlings to create the whole stand, so establishment rates are higher. Overseeding adds plants into an existing lawn. Applying a new-lawn rate into dense existing turf can create excessive seedling competition without solving the reason the lawn was thin.
Before overseeding, decide whether the remaining lawn is worth keeping and whether seed can reach soil. Compaction, deep thatch, shade, poor timing, or irrigation problems can defeat a mathematically correct seed quantity.
Use the label rate to compare bag sizes.
Coverage claims can refer to different tasks. The same product may list one coverage area for new-lawn establishment and a much larger area for overseeding. Compare the package weight with the actual pounds required for your task.
| If you need | Typical planning move | Why |
|---|---|---|
| About 9 lb | 10 lb package | Small margin without a large leftover amount. |
| About 18 to 24 lb | 25 lb package | Covers the working range for many products sold in that size. |
| About 38 lb | 40 or 50 lb total | Choose available package combinations after checking the label and storage plan. |
Do not deliberately over-apply the leftover seed just to empty the bag. Save viable seed under appropriate storage conditions or buy a package combination closer to the calculated requirement.
Calculator questions
How much grass seed do I need for 1,000 square feet?
It depends on grass type and whether you are starting bare soil or overseeding. Tall fescue may use roughly 6 to 8 lb per 1,000 sq ft for establishment, while Kentucky bluegrass uses substantially less.
How much grass seed do I need for an acre?
One acre is 43,560 square feet. Multiply 43.56 by the seed rate per 1,000 square feet. For example, 6 lb per 1,000 sq ft works out to about 261 lb per acre.
Should I use the new-lawn or overseeding rate?
Use the new-lawn rate when seed is establishing most of the turf in bare or substantially renovated soil. Use the overseeding rate when viable existing grass remains and new seed is being added to increase density.
What if my bag gives a different seeding rate?
Use the product label. Select “Use my seed label rate” in the calculator and enter the low and high rates shown for your task.
Should I buy extra seed?
A modest package-size margin is practical, but do not intentionally exceed the recommended application rate. Package planning and application rate are separate decisions.
Quantity planning only
Area × rate per 1,000 sq ft; label-specific rate can replace the defaults.
Practical help for home and yard