Lawn Seed Quantity Calculator
Estimate grass seed kilograms and whole bags from lawn area, the selected seed blend's sowing rate and an adjustable allowance.
Your results
Calculation breakdown
- Seed kilograms
- area ÷ 100 × label kg/100 m² × allowance factor
Worked example
A 600 m² lawn sown at the selected label rate of 3 kg per 100 m² needs 19.8 kg with 10% allowance, so four 5 kg bags are required.
Assumptions
- The entered rate applies to the chosen seed blend and use.
- Area excludes surfaces that will not be seeded.
Sources
Rates effective 23 August 2026.
How this calculator works
Seed blends and establishment methods have different recommended sowing rates, so this tool does not invent a universal rate. It scales the current supplier figure from 100 square metres to the measured lawn, applies an allowance for calibration and edge losses, and rounds the purchase to whole bags.
Frequently asked questions
Where should the sowing rate come from?
Use the current label or supplier instructions for the exact seed blend, season, new-lawn or oversowing use and application method.
Is a higher seed rate always better?
No. Excessively dense sowing can increase competition or disease risk, so stay within product and local turf guidance.
Does the result include fertiliser?
No. Seed, starter fertiliser, soil preparation and irrigation requirements should be planned as separate products and tasks.