Grass Seed Calculator
Estimate Lawn Seed Requirements & Costs
Are you planting a lush new green lawn or filling in thin spots on your turf? Planting grass from seed is an affordable alternative to sod. Using the right amount of seed is critical: too little means a patchy, weed-prone yard, while too much causes crowding and lawn disease. Use our free calculator to estimate the exact pounds of seed needed and the purchase cost.
Example: 50×40 ft Tall Fescue lawn (2,000 sq ft) = approx. 16 lbs of seed = $72.00. Enter dimensions and click Calculate.
Turfgrass Characteristics Comparison
| Grass Species | Seeding Rate (New Lawn) | Germination Time | Traffic Tolerance | Sun/Shade Preference |
|---|---|---|---|---|
| Tall Fescue | 8 lbs / 1000 sq ft | 7 – 12 days | High | Sun or Partial Shade |
| Kentucky Bluegrass | 3 lbs / 1000 sq ft | 14 – 21 days | Medium-High | Full Sun |
| Perennial Ryegrass | 9 lbs / 1000 sq ft | 3 – 7 days | High | Full Sun to Light Shade |
How to Calculate Grass Seed
Sizing your grass seed order depends on your total lawn area and whether you are starting from bare soil or overseeding to thicken an established lawn:
- Overseeding Rate: Overseeding requires exactly **half** the amount of seed as planting a brand new bare lawn, as you are simply filling gaps between existing grass plants.
- Seed Spreading Rates: Seed density varies by species. Tall Fescue has large seeds and requires about 8 lbs per 1,000 sq ft. Kentucky Bluegrass has very tiny seeds, so a lower weight of 3 lbs per 1,000 sq ft covers the same area with millions more seeds. Ryegrass has heavy seeds and requires 9 lbs per 1,000 sq ft.
Lawn Seed Rates Comparison Table
| Grass Type | New Lawn Rate (per 1k sq ft) | Overseed Rate (per 1k sq ft) | Germination Time |
|---|---|---|---|
| Tall Fescue | 8 pounds | 4 pounds | 7 – 12 days |
| Kentucky Bluegrass | 3 pounds | 1.5 pounds | 14 – 21 days |
| Perennial Ryegrass | 9 pounds | 4.5 pounds | 5 – 7 days |
Authoritative References & Standards:
- National Turfgrass Evaluation Program (NTEP) - Performance evaluations for lawn seed cultivars.
- USDA Natural Resources Conservation Service - Ground cover establishment and seeding rate guidelines.