Lawn Seed Calculator

Estimate how much grass seed, topsoil and starter fertiliser a lawn needs from the area, the grass type and the sowing method. Choose a grass, a new lawn or overseeding, and enter the area and an optional topsoil depth. This is an approximate estimate for buying materials, not a quote; follow the seed supplier's recommended rate. All processing runs locally in your browser. Your data is not uploaded to any server. 100% Local

How to Use the Lawn Seed Calculator

Choose your units, a grass type and a sowing method, then enter the lawn area and an optional topsoil depth. Press Calculate seed to see the seed weight, the starter fertiliser and the topsoil volume.

What it accounts for

• Seed weight is the area multiplied by the seed rate and the sowing factor.
• Starter fertiliser is a reference allowance of about 25 g per square metre.
• Topsoil volume is the area multiplied by the depth, when a depth is given.

Getting a better number

Seed rates depend on the mix and the season, and overseeding uses about half the rate of a new lawn. Widen or divide very large areas to keep the cover even, and water regularly while the seed establishes.

Features

• Grass seed weight in kilograms and pounds
• Starter fertiliser reference and topsoil volume
• Grass type and new lawn or overseeding
• All processing runs locally in your browser. Your data is not uploaded to any server.
• Results are approximate estimates; check the supplier's guidance and do a soil test before fertilising.

Sow when the soil is warm and moist, and keep the seedbed moist until the new grass is established.

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