Lawn Seed Calculator
Calculate exactly how much grass seed you need based on lawn area, grass type, and seeding purpose.
Did this tool work for you?
How to use this calculator
Seeding rates vary by grass species and purpose. New lawns require the full rate; overseeding uses half; patching uses 150% to achieve rapid coverage.
- 1
Measure your lawn area in square metres.
- 2
Select the grass species you are planting.
- 3
Choose whether you are establishing a new lawn, overseeding, or patching.
- 4
The calculator shows seed weight in kg and lbs at the recommended rate.
Frequently asked questions
What is the best time to sow grass seed?
Cool-season grasses (fescue, bluegrass, ryegrass) do best sown in early autumn or early spring. Warm-season grasses (bermuda, zoysia, buffalo) are best sown in late spring or early summer when soil temperatures reach 18–24 °C.
Why does bermuda grass need so little seed?
Bermuda grass seeds are tiny and spread aggressively via stolons, so a very low seeding rate (around 5 g/m²) is sufficient. Over-seeding bermuda is wasteful and can cause overcrowding.
Do I need to prepare the soil before seeding?
Yes — loosen the top 5–10 cm of soil, remove weeds and debris, level the surface, and lightly rake after spreading seed. Good seed-to-soil contact is essential for germination.
Lawn Seed Calculator — Kg, Lbs & Seeding Rates
Grass Seed Rates by Species
Seeding rates vary significantly between grass species. Fine fescue needs 30 g/m² for a new lawn while bermuda grass requires only 5 g/m². Using the right rate prevents both thin coverage and wasteful over-application.
New Lawn vs Overseeding vs Patching
A new lawn requires the full species rate. Overseeding an existing lawn (adding seed to thin areas) uses half the rate to avoid competing with established grass. Patching bare spots uses 150% of the base rate to ensure rapid, dense coverage.
Tips for Successful Lawn Seeding
Water newly seeded areas lightly 2–3 times daily until germination occurs (typically 7–21 days depending on species). Avoid heavy foot traffic for 6–8 weeks. Apply a starter fertiliser at seeding time to encourage root development.
Learn more from an authoritative source:
WikipediaMulch Calculator
Calculate how many cubic yards or cubic metres of mulch you need for a garden bed, plus bags required.
Raised Bed Soil Calculator
Calculate how much soil and compost you need to fill a raised garden bed, with mix breakdowns.
Plant Spacing Calculator
Calculate how many plants fit in a garden bed using square grid or triangular offset planting patterns.
Watering Schedule Calculator
Calculate how much water your garden needs per week based on plant type, climate, and recent rainfall.
Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →