From measured space to purchasable material
New lawn establishment and overseeding can use different seed rates even when they use the same product. This calculator accepts separate areas and label rates for each job, then combines the pounds needed before rounding to bags. It also displays the coverage that one bag would provide at each rate. The starting rates are examples rather than recommendations for a grass variety. Use the seed label and suitable regional guidance to choose a rate, then measure only the areas actually being seeded.
Measure, select yield and round the order
- Separate bare-ground establishment from overseeding area.
- Enter each rate from the chosen seed label.
- Round the combined product weight to complete bags.
Net requirement and purchase calculation
A worked example
500 ft² of new lawn at 6 lb/1,000 ft² uses 3 lb. Overseeding 1,000 ft² at 3 lb/1,000 ft² adds 3 lb; 5% handling allowance gives 6.3 lb.
Grass Seed: what changes the result?
Compare the layer or product assumptions behind the material order. The comparisons below are calculated from this page’s default example. Each row changes only the named input; all other inputs stay at their displayed example values. These are mathematical scenarios, not measurements from a completed project.
| Changed assumption | Default input | Comparison input | Result: default → comparison |
|---|---|---|---|
| New lawn area | 500 sq ft | 600 sq ft | New lawn seed before allowance: 3 → 3.6 lb Combined seed with allowance: 6.3 → 6.93 lb |
| New lawn rate per 1,000 ft² | 6 lb/1,000 sq ft | 7.2 lb/1,000 sq ft | New lawn seed before allowance: 3 → 3.6 lb Combined seed with allowance: 6.3 → 6.93 lb |
| Overseeding area | 1,000 sq ft | 1,200 sq ft | Overseeding seed before allowance: 3 → 3.6 lb Combined seed with allowance: 6.3 → 6.93 lb |
| Overseeding rate per 1,000 ft² | 3 lb/1,000 sq ft | 3.6 lb/1,000 sq ft | Overseeding seed before allowance: 3 → 3.6 lb Combined seed with allowance: 6.3 → 6.93 lb |
Displayed values are rounded. Whole-pack results change in steps; continuous quantities may change before a new pack is needed. To compare your actual project, enter your dimensions above, save a scenario, then change one assumption.
Coverage, allowance and purchasing limits
- Seed mixtures differ in species, coatings and recommended rates.
- Spreader settings are product- and equipment-specific, not a direct conversion from pounds.
- This quantity estimate does not choose seeding season or irrigation frequency.
Frequently asked questions
Can I calculate new lawn and overseeding together?
Yes. The two areas use separate entered rates and combine into one purchase quantity.
What rate should I use for grass seed?
Use the label for your exact product and intended job. The default values are examples.
Does coated seed weigh the same as pure seed?
The product can contain coating material. Follow coverage and rate information on that product’s package.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.