Construction & trade New Zealand
Turf Calculator New Zealand
A new lawn goes down in rolls that cover a fixed area, and the soil underneath matters as much as the turf. Enter the lawn area, the size of a roll and the depth of soil to be laid to see how many rolls to order, how much soil to buy and the rough cost.
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Check with your supplier; roll and slab sizes vary.
Topsoil under the turf; 75 to 100 mm is common.
Rolls to order
—Turf area to order
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Soil needed
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Soil weight (at 1.3 t/m³)
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Rough cost of turf
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The working
How many rolls of turf do I need?
Divide the lawn area by the area of a roll and add a margin for cuts. A 60 m² lawn with rolls of 1 m² and 5% extra needs 63 rolls. A 75 mm layer of soil under it is 4.5 m³.
Preparing the ground
Remove old grass and weeds, loosen the soil and add topsoil to the depth you plan. Level it with a rake and roll lightly so there are no hollows. Water the soil the day before. Poor preparation is the most common reason new lawns fail, and it is much harder to fix once the turf is down.
Laying and aftercare
Start along a straight edge, stagger the joins like bricks and press the rolls tightly together without stretching. Water well straight after laying, and keep the lawn moist for the first few weeks until the roots take. Avoid walking on it for the first couple of weeks, and do the first mow when the grass is about a third taller than the cutting height.
To prepare the soil, use the topsoil calculator.
How this is calculated
The rule, step by step, so you can check any figure by hand.
rolls = lawn area × (1 + cuts ÷ 100) ÷ area of one roll, rounded upsoil volume = lawn area × soil depth (in metres)soil weight = soil volume × about 1.3 tonnes per cubic metrecost = rolls × roll area × price per m²
Turf is perishable: it should be laid within a day of delivery, so measure carefully and order the right amount rather than too much. A margin of 5% covers cuts on a simple rectangle; allow 10% or more if the lawn has curves, garden beds or odd corners.
The soil under the turf is what the new lawn roots into. Compacted clay or builder's fill needs loosening and topsoil on top, otherwise the turf struggles. Level the area, rake it fine and roll it lightly before laying.
A worked example
A 60 m² lawn, rolls of 1 m², 5% extra, 75 mm of soil.
- Turf to order63 m²
- Rolls63
- Soil4.5 m³
- Soil weight5.9 tonnes
63 rolls and 4.5 m³ of soil.
Book delivery for the day you will lay it.
Choosing a turf variety
Choose a turf to suit the amount of sun, how much wear it will get and local conditions. Warm-season grasses grow in the heat and go brown in cold; cool-season grasses stay green in winter. Ask a local supplier which grows best in your area.
What it leaves out
Irrigation, fertiliser and the slope of the site are not modelled. The cost is the turf only; delivery and soil prices are extra.
What this calculator does not do
- Flat rectangular areas
- Roll size from your supplier
- Soil weight is typical
- An estimate for ordering
Common questions
How many rolls of turf do I need?
Lawn area plus about 5% for cuts, divided by the roll area.
How deep should the soil be under turf?
About 75 to 100 mm of good topsoil.
How soon must turf be laid?
Within a day of delivery.
How much extra should I order?
About 5% for simple shapes and 10% for curves.
When should I water?
Straight after laying and regularly for the first few weeks.
Where these numbers come from
- Wolfram MathWorld — cuboid Volume of a box: length × width × height. Fixed formula, nothing to go out of date
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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