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Trade & construction Australia

Flooring Calculator Australia

Flooring is sold in packs that cover a fixed area, so you buy more than the room measures to allow for cuts and offcuts. Enter the room size, the waste allowance and the pack coverage to see how many packs to buy, the underlay area and the length of skirting.

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10% for a straight layout, 15% or more for diagonal or patterned.

On the pack label. Many laminate and plank packs cover about 2 m².

Subtracted from the skirting length.

Packs to buy

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Floor area

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Area with waste

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Underlay to buy

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Skirting length

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Rough cost

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The working

    How much flooring do I need?

    Multiply length by width, add 10% for cuts and divide by the area of a pack, rounding up. A 5 m by 4 m room is 20 m², 22.0 m² with waste, which is 10 packs of 2.2 m² each. Diagonal layouts and patterns need 15% or more.

    Measuring the room

    Measure the length and width at the widest points, and add alcoves, bay windows and cupboards as separate rectangles. Leave out fixed items such as a kitchen island or a fireplace hearth. Include the area under a door, since the floor continues through. If the room is not square, split it into rectangles and add them.

    Choosing and laying

    Laminate, vinyl planks and engineered timber click together over underlay and float, while solid timber is nailed or glued. Floating floors need an expansion gap of around 10 mm at the walls, which skirting hides. A moisture barrier is needed over concrete slabs, and the subfloor must be flat and dry.

    To cover a bigger project, use the tile calculator.

    How this is calculated

    The rule, step by step, so you can check any figure by hand.

    • floor area = length × width
    • area with waste = floor area × (1 + waste ÷ 100)
    • packs = area with waste ÷ coverage of one pack, rounded up
    • underlay area = floor area
    • skirting length = 2 × (length + width) − door openings

    Flooring has to be cut around the edges and at the end of each row, and the offcut from one row can often start the next. A straight layout wastes about 10%; diagonal and herringbone layouts waste 15 to 20%; and a room with many corners or alcoves wastes more. Buying one extra pack is cheap insurance, because stock and batches change, and a later pack may not match.

    Buy all packs from the same batch and keep a spare for repairs. Let the planks sit in the room for a day or two before laying so they match its temperature and humidity.

    A worked example

    A 5 m by 4 m room, 10% waste, packs of 2.2 m².

    1. Floor area20 m²
    2. With waste22.0 m²
    3. Packs10
    4. Underlay20 m²
    5. Skirting18 m

    10 packs.

    Add one spare pack if the budget allows.

    Underlay and extras

    Underlay is bought by area, usually in rolls, and should match the flooring: acoustic underlay for apartments, moisture barriers over concrete. Also budget for trims, transition strips at doorways and any adhesive.

    What it leaves out

    Stairs, irregular rooms and the pattern repeat of printed vinyl are not modelled. Check the manufacturer's laying guide for the waste they recommend.

    What this calculator does not do

    • Rectangular rooms
    • Waste allowance is your choice
    • Pack coverage from the label
    • An estimate for buying

    Common questions

    How much extra flooring should I buy?

    About 10% for a straight layout and 15% or more for diagonal.

    How do I work out the number of boxes?

    Divide the area with waste by the area of a pack and round up.

    Do I need underlay?

    Usually, for floating floors.

    How much skirting do I need?

    The room's perimeter less door openings.

    Should I buy a spare pack?

    Yes, for repairs, because later batches may not match.

    Where these numbers come from

    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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