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Lawn Calculators

Grass Seed Calculator

Grass seed needed for a new lawn or overseeding, with the cost.

Enter values

Results update as you type.

Result

Seed needed

4.12 kg

Sow when the soil is above 8 °C and keep it damp — seed that dries out after germinating will not recover.

Base requirement
3.5 kg
Sowing rate
35 g/m²
Extra for germination loss
0.62 kg
Bags to buy (1 kg)
5
Coverage per kg
28.6 m²
Seed cost
$49.41

About the Grass Seed Calculator

Grass seed needed for a new lawn or overseeding, with the cost.

Also known as: lawn seed calculator, how much grass seed, overseeding rate, seed per square meter.

How to use this calculator

  1. Enter lawn area, purpose, expected germination, price per kg.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

seed = area × sowing rate ÷ germination rate

Worked example

Using the values pre-filled in the calculator above:

  • Lawn area = 100 m²
  • Purpose: New lawn (35 g/m²)
  • Expected germination = 85 %
  • Price per kg = 12

the calculator returns:

  • Seed needed: 4.12 kg
  • Base requirement: 3.5 kg
  • Sowing rate: 35 g/m²
  • Extra for germination loss: 0.62 kg