Free estimate — verify against local code before building
Grass Seed Calculator
Convert lawn area and an editable seeding rate into pounds, whole bags, and optional cost.
What this calculator includes
Enter the lawn area, choose new establishment or overseeding, and select a broad grass family to load an editable starting rate. The calculator converts that rate to total pounds, rounds to whole bags, and optionally prices the order. Sun condition is kept as a visible site-selection reminder, but it does not silently increase seed quantity. The seed label and local extension guidance should replace the starting rate.
How to use this grass seed calculator
- 01
Measure the lawn
Add lawn sections and subtract buildings, beds, paving, and other areas that will not be seeded.
- 02
Choose the project
New lawns normally use more seed than overseeding an established stand.
- 03
Replace the starting rate
Use the exact seed label or local extension recommendation for the selected species and season.
- 04
Buy whole bags
Round up to the selected bag size, then store unused seed cool and dry according to its label.
Worked example
Example: overseeding 5,000 sq ft
At 4 lb per 1,000 sq ft, a 5,000 sq ft lawn needs 20 lb of seed. With 10 lb bags, the purchase quantity is 2 bags. Partial sun is a species-selection reminder and does not change the entered label rate.
Practical buying and overage guidance
Compare the seed tag, not just the front label: species percentages, cultivar names, germination, purity, weed seed, test date, and coverage rate all matter. Buy for the site and planting window rather than choosing only by bag price.
Continue the project
Refresh Landscape Beds and Lawn
Measure beds and lawn, compare mulch bags or bulk delivery, plan decorative gravel or sod, estimate loads, and price the complete landscape job.
Open the project workflow →Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- USDA Plant Hardiness Zone Map (opens in a new tab)
Regional climate context; hardiness zones alone do not select a turf species or planting date.
- National Turfgrass Evaluation Program (opens in a new tab)
Independent cultivar performance data by location and trial conditions.
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends heavily on species, seed blend, germination, and whether the work is new establishment or overseeding. Cool-season mixtures often use higher pound rates than bermudagrass. Enter the rate printed on the exact seed label.
Is overseeding the same rate as a new lawn?
Usually not. Overseeding rates are commonly lower because existing turf remains. Bare or badly damaged areas may need separate treatment rather than one blended rate.
Should shade increase the seed amount?
Not automatically. More seed does not fix unsuitable species, dense shade, tree-root competition, drainage, or soil problems. This calculator leaves the entered label rate unchanged; choose a suitable blend and obtain local guidance.
When should I seed my lawn?
The best window depends on grass species and regional soil temperatures. Cool-season and warm-season grasses have different planting seasons, so use local extension guidance and the seed label.
Does the calculator account for germination rate?
No. Seed labels disclose germination and purity. The entered application rate should already reflect the product recommendation; do not silently inflate it without understanding the label.