How much grass seed per m²?

25–35 g/m² for a new lawn, 15–20 g/m² for overseeding.

When should I sow grass?

In late spring or late summer when the soil is warm and moist.

Grass Seed Calculator

Calculate how much grass seed you need from the area to be sown and the seeding rate.

Area to sow: 100 m²

Seeding rate: 30 g/m²

3.00 kg

Seed needed

Seed in grams	3,000 g
Seed in kg	3.00 kg

ℹ️ New lawn 25–35 g/m², overseeding 15–20 g/m².

This grass seed calculator estimates how much seed you need based on the area to be sown and the seeding rate. You get the requirement in both grams and kilograms.

How the calculator works and what it’s for▾

How the seed requirement is calculated

The tool multiplies the area to sow by the seeding rate to find the amount of seed in grams. This is then converted to kilograms to make buying easier.

For example, a 100 m² area at a seeding rate of 30 g/m² means 3000 grams, that is 3 kilograms of seed.

Inputs and results

Enter the area to sow in square metres and the seeding rate in grams per square metre. The result shows the seed needed in grams and in kilograms.

The kilogram figure helps you compare pack sizes in the shop, since seed is usually sold by the kilogram.

Who it is for

It is useful when starting a new lawn and when overseeding an existing one. It helps you buy the right amount of seed without a needless surplus.

Recommended seeding rates

A new lawn typically calls for 25–35 g/m², while overseeding uses 15–20 g/m². Sowing too thinly leaves gaps and lets weeds take hold, so choose the rate to match the purpose.

🔄 Reviewed June 2026