About this calculator
Estimates lawn installation quantities for a rectangular area: grass seed by sowing rate or turf rolls by roll coverage, topsoil volume by depth, and optional fertiliser.
Formula
area = length × width
seed mass = area (m²) × sowing rate (g/m²) / 1000, then + waste% [seed mode]
turf rolls = ceil(area / roll area), then + waste% [turf mode]
topsoil volume = area × topsoil depth
fertiliser mass = area (m²) × fertiliser rate (g/m²) / 1000 [optional]
Worked example
Defaults: 10 m × 5 m area, seeded at 30 g/m², 5% waste, 100 mm topsoil, fertiliser at 30 g/m².
area = 50 m²
seed mass = 50 × 30 / 1000 = 1.5 kg; incl. waste = 1.5 × 1.05 = 1.575 kg
topsoil = 50 m² × 100 mm = 5 m³
fertiliser mass = 50 × 30 / 1000 = 1.5 kg
FAQ
Why are the sowing rate, turf roll area, and fertiliser rate adjustable? They depend on the grass species, soil condition, and specific turf or fertiliser product — this calculator converts a rate you supply into quantities, it doesn't set the rate itself.
Why doesn't the calculator cite a standard?
No standard governs a generic lawn quantity take-off; these are supplier and product figures,
not a normative constant, so meta.standards is left empty.
Assumptions and limits
Sowing rate, turf roll coverage, topsoil depth, and fertiliser rate are all disclosed estimates you should adjust to match your own product and site conditions.