Gardening
Lawn Area Calculator
Lawn area for irregular gardens, with the seed, fertiliser and mowing time it implies.
area = Σ shapes − beds and paths
Also called garden area calculator · grass area
Garden, Farm & Pets · 11 calculators
Gardening Calculators
Garden and lawn area, soil, mulch and compost volumes, seeds, plant spacing, fertiliser, watering, raised beds and pots.
Gardening
Soil Volume Calculator
Topsoil or compost needed for a bed or area, in cubic metres, bags and tonnes.
volume = area × depth × (1 + settlement)
Also called topsoil calculator · how much soil do i need
Gardening
Mulch Calculator
Mulch needed for beds and borders, in cubic metres, bags and tonnes.
volume = area × depth
Also called bark chip calculator · how much mulch
Gardening
Compost Calculator
Compost needed for beds and borders, and how much your kitchen waste will make.
volume = area × depth
Also called compost quantity calculator · how much compost
Gardening
Seed Quantity Calculator
Seeds needed for a planting area, allowing for germination rate and thinning.
seeds = plants wanted ÷ germination rate …
Also called how many seeds do i need · seed packet calculator
Gardening
Plant Spacing Calculator
How many plants fit a bed at a given spacing, in grid or triangular layout.
plants = (usable length ÷ spacing + 1) × …
Also called how many plants per square meter · planting density calculator
Gardening
Grass Seed Calculator
Grass seed needed for a new lawn or overseeding, with the cost.
seed = area × sowing rate ÷ germination r…
Also called lawn seed calculator · how much grass seed
Gardening
Fertilizer Calculator
Fertiliser needed for an area at a target nitrogen rate, from the NPK analysis.
product = area × nitrogen target ÷ nitrog…
Also called lawn feed calculator · npk calculator
Gardening
Watering Calculator
Water needed for a garden or lawn, per session and per week.
litres = area × millimetres needed (1 mm …
Also called garden watering calculator · how much to water plants
Gardening
Raised Bed Soil Calculator
Soil mix for raised beds, split into topsoil, compost and drainage material.
volume = length × width × height × fill l…
Also called raised bed calculator · garden bed soil
Gardening
Pot Volume Calculator
Compost needed to fill plant pots of any shape and size.
Tapered pot: V = πh(r₁² + r₁r₂ + r₂²) ÷ 3
Also called plant pot size calculator · container volume
Key gardening formulas
| Lawn Area | area = Σ shapes − beds and paths |
|---|---|
| Soil Volume | volume = area × depth × (1 + settlement) |
| Mulch | volume = area × depth |
| Compost | volume = area × depth · compost yield ≈ 30% of raw waste by weight |
| Seed Quantity | seeds = plants wanted ÷ germination rate × (1 + thinning) |
| Plant Spacing | plants = (usable length ÷ spacing + 1) × (usable width ÷ row spacing + 1) |
| Grass Seed | seed = area × sowing rate ÷ germination rate |
| Fertilizer | product = area × nitrogen target ÷ nitrogen percentage |
| Watering | litres = area × millimetres needed (1 mm over 1 m² = 1 litre) |
| Raised Bed Soil | volume = length × width × height × fill level × beds |