Grass Seed Calculator
Calculate seed weight from lawn area and the new-lawn or overseeding application rate printed on your chosen seed product.
Instant estimate · No sign-up · Your measurements stay in your browser
Project details
Enter your measurements
Enter your project measurements. Planning defaults are identified where used. After your first calculation, edits update the estimate automatically.
Project estimate
Results
Enter your measurements, then select Calculate.
How to use this calculator
Seed products use different application rates for new lawns and overseeding, as well as for different species, blends, and conditions. Enter the applicable rate from the package you will use instead of relying on a universal assumption.
- Measure the rectangular lawn area.
- Find the new-lawn or overseeding pounds-per-1,000-sq-ft rate that applies to your project on the product package.
- Enter that rate and choose an optional buffer.
- Compare the result with available package weights and continue following the product label.
Formula and methodology
Lawn area = length × width. Seed pounds = (area ÷ 1,000) × product application rate. Recommended pounds add the optional buffer.
Important: This tool calculates quantity from the rate you supply; it does not select a grass type or guarantee establishment.
How accurate is this estimate?
Lawn area is calculated directly from your dimensions. Seed weight then depends on the new-lawn or overseeding application rate you enter, and the recommended quantity adds only your selected optional buffer. Confirm the applicable rate and package weight on the seed product before purchasing and applying it.
Worked example
A 60 ft × 40 ft lawn is 2,400 sq ft. If the selected product’s applicable rate is 5 lb per 1,000 sq ft, the calculated need is 12 lb. A 10% buffer would make the recommendation 13.2 lb.
Before you buy
- Use the label rate for either new seeding or overseeding as applicable.
- Subtract buildings, beds, pavement, and other unseeded areas.
- Buy by weight, then follow product directions for timing, preparation, spreading, and watering.
Frequently asked questions
What application rate should I enter?
Use the new-lawn or overseeding rate printed on the package for your specific seed product and project. Do not substitute one project type’s rate for the other.
Can I set the buffer to zero?
Yes. The default is zero because the product rate already controls the base quantity.
How should I handle an irregular lawn?
Break it into measurable rectangles, calculate each area, and add them. Subtract large unseeded areas.