Grass Seed Calculator
Seed needed for a new lawn, bags and cost, with the lighter rate for overseeding an existing one.
Results
Seed needed
4.200
kg
Cement bags
1
Cost
28.00
Seed needed
3.000
kg
Area
142.9
m²
What this tool does
A new lawn from bare soil wants around 35 grams per square metre; overseeding a thin existing lawn needs about 25. Sowing heavier does not give a thicker lawn — the seedlings compete, go spindly and are more prone to disease. Take the rate from the bag, because fine fescue mixes and ryegrass mixes differ substantially in seed size.
Formula
seed = area × dose
Variables
| Symbol | Meaning | Unit |
|---|---|---|
ar | Area | m² |
rt | Sowing rate | g/m² |
bw | Cement bag weight | kg |
bp | Price per bag | — |
KG | Seed needed | kg |
NB | Cement bags | — |
CO | Cost | — |
OV | Seed needed | kg |
CM | Area | m² |
Worked example
- Area120 m²
- Sowing rate35 g/m²
- Cement bag weight5 kg
- Price per bag28
- Seed needed4.200 kg
- Cement bags1
- Cost28.00
- Seed needed3.000 kg
- Area142.9 m²
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- Coverage and consumption figures vary between products. Take the values from the manufacturer's datasheet for the product you are actually using.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.