Grass seed calculator
This grass seed calculator works from lawn area and lawn type: 1,000 sq ft of general-use lawn needs about 5 lb of seed (roughly 5 lb per 1,000 sq ft), plus starter fertilizer. It also gives the number of bags, sod and topsoil.
Example: Units: Imperial (sq ft, lb, in) · Lawn area 1,000 · Lawn type: General-use lawn (standard) · Seed bag size 10 · Topsoil layer 1 → Result: Seed: 5.12 lb · bags: 1. Source: Wikipedia – Rasen (Saat, Pflege). Updated: .
How it is calculated
The seeding rate depends on the lawn type: general-use lawn needs about 20 to 30 g of seed per m² (4 to 6 lb per 1,000 sq ft), play and sports turf 25 to 35 g, fine ornamental lawn 10 to 20 g, overseeding 10 to 20 g. The calculator uses the midpoint as the guideline and shows the range.
How it is calculated
- Seed: area in m² × rate in g/m² ÷ 1000 = kg
- Bags: seed amount ÷ bag size, rounded up
- Sod: area × 1.05 (5% waste for edges and corners)
- Starter fertilizer: area × 30 g/m² (a typical manufacturer value)
- Topsoil: area × layer depth; 3 cm is 0.03 m³ per m²
How to use it
Enter the area, choose the lawn type and the bag size. Example: 100 m² of general-use lawn needs 2.5 kg of seed (range 2 to 3 kg), one 5 kg bag is enough, plus 3 kg of starter fertilizer and 3 m³ of topsoil at 3 cm depth. For US units switch to “Imperial”; results then appear in lb, sq ft and ft³.
Frequently asked questions
How much grass seed do you need per square foot?
About 4 to 6 lb per 1,000 sq ft for a general-use lawn, which equals 20 to 30 g per m². Sports turf and shade mixes need a bit more.
How much seed do you need for 1,000 square feet?
Around 5 lb for a general-use lawn. Check the rate printed on your seed mix, because species differ.
What about overseeding?
Overseeding needs only 10 to 20 g per m² (2 to 4 lb per 1,000 sq ft). Rake or dethatch first so the seed touches soil.
How much sod should I order?
The area plus about 5% for waste; for 100 m² that is 105 m². Lay sod on the day it is delivered.
Why not just spread more seed?
Over-dense lawns establish poorly: seedlings compete and fungal diseases spread more easily. Even spreading matters more than a high rate.
Sources and legal basis
- Wikipedia – Rasen (Saat, Pflege)
- FLL – Regel-Saatgut-Mischungen (RSM) for lawns
- RHS – Lawn seed and sowing
- Penn State Extension – Lawn establishment (seeding rates)
As of: · Editorial policy
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