Gardening Calculations: Soil, Spacing and Seeding
Plan a productive garden with confidence — how much soil to buy, how far apart to space plants and trees, how much seed and fertiliser you need, and the watering to keep it all thriving.
Grass Seed Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Grass seed needed
3.50
- Grass seed (grams)
- 3,500
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Grass Seed Calculator
The Grass Seed Calculator works out your grass seed needed, along with 1 related figure in an instant. Enter lawn area and seeding rate and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the lawn area.
- Enter the seeding rate.
- Read off your grass seed needed, together with grass seed (grams) — the calculator updates automatically, with no button to press.
Formula
The Grass Seed Calculator uses the formula:
Grass seed needed = Lawn area × Seeding rate ÷ 1000
Worked example
For example, with lawn area of 100 m² and seeding rate of 35 g/m², the grass seed needed is 3.50.
| Lawn area | 100 m² |
|---|---|
| Seeding rate | 35 g/m² |
| Grass seed needed | 3.50 |
|---|---|
| Grass seed (grams) | 3,500 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Area
- The amount of two-dimensional space a shape covers, measured in square units.
Frequently asked questions
Multiply the area by the seeding rate. A 100 m² lawn at 35 g/m² needs 3.5 kg of seed.
New lawns often use 30–50 g/m², while overseeding an existing lawn uses about half that. Check your seed packet.
A little extra covers patchy spots and birds taking some seed. Around 10% more is a safe margin.
Spring and early autumn suit most grasses, when soil is warm and moist enough for good germination.
The Grass Seed Calculator uses the formula: Grass seed needed = Lawn area × Seeding rate ÷ 1000. For example, with lawn area of 100 m² and seeding rate of 35 g/m², the grass seed needed is 3.50.
Enter the lawn area. Enter the seeding rate. Read off your grass seed needed, together with grass seed (grams) — the calculator updates automatically, with no button to press.
Related guides
Grass Seed Table: Grass seed needed by Lawn area
Reference table of grass seed needed for Grass Seed across a range of lawn area values — exact, engine-computed figures you can read off at a glance.
How to Calculate Grass Seed: Formula, Steps & Examples
Learn how to calculate Grass Seed — the formula explained step by step, with worked examples and a free calculator to check your answer.
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