Work out how many boxes of flooring a room needs. Enter the dimensions, pick a material, and get boxes, underlayment, trim and a total cost estimate.
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Flooring is sold in boxes, not square feet, and every material covers a different area per box. This flooring calculator works out how many boxes you need from the room dimensions and the material you’re installing. It handles rectangles, L-shapes, and direct area entry, then adds waste, calculates underlayment rolls, and counts trim pieces by perimeter.
Ten flooring types are included: solid hardwood, engineered, laminate, luxury vinyl plank, ceramic tile, porcelain tile, vinyl sheet, carpet tile, broadloom carpet, and custom. The tool loads coverage per box and plank dimensions automatically for each. Enter your local prices and it returns the full cost with a per-square-metre or per-square-foot breakdown.
How to Use the Flooring Calculator
Pick the unit system: metric (m² / m) or imperial (ft² / ft).
Choose the room shape: rectangle, L-shape, or direct area.
Enter the dimensions. Rectangle uses length and width.
Set how many identical rooms you’re flooring.
Pick the flooring type from the dropdown. Coverage loads automatically.
Adjust the waste factor. Ten percent is the standard starting point.
Set underlayment coverage, door width to deduct, and trim piece length.
Enter your prices for flooring, underlayment, trim, adhesive, and labor.
The Summary tab shows total area, boxes, underlayment rolls, trim, and total cost. Detailed Breakdown lists every intermediate figure.
Flooring quantity comes from area divided by coverage, with waste added. Trim comes from perimeter, minus door openings.
Formula: Rectangle area = Length × Width
Formula: L-shape area = (Overall length × Overall width) − (Cutout length × Cutout width)
Formula: Total area = Room area × Number of rooms
Formula: Area with waste = Total area × (1 + Waste %)
Formula: Boxes needed = ⌈ Area with waste ÷ Coverage per box ⌉
Formula: Pieces per box = ⌊ Coverage per box ÷ Area per piece ⌉
Formula: Total pieces = ⌈ Area with waste ÷ Area per piece ⌉
Formula: Underlayment rolls = ⌈ Total area ÷ Coverage per roll ⌉
Formula: Trim length = Total perimeter − Door width
Formula: Trim pieces = ⌈ Trim length ÷ Trim piece length ⌉
Waste applies to flooring, not to underlayment. Underlayment rolls are calculated from the bare room area, since underlayment is easier to piece together and doesn’t need pattern waste. Trim is calculated from perimeter with door widths deducted, since a door doesn’t need trim.
The L-shape uses the outer rectangle minus the cutout rectangle. That’s the common corner-cutout shape for a room that wraps around a closet, staircase, or exterior corner. The perimeter formula for an L-shape is the same as the outer rectangle’s perimeter because the cutout adds and removes equal edges.
Piece counts matter for plank and tile. A box of laminate covers 2.23 m² and holds about 10 planks, so a 30 m² floor with waste needs 15 boxes and about 149 planks. The tool reports both, since some installers like to know the plank count for layout planning.
Worked Example: Three 5 m × 4 m Bedrooms, Laminate
Say you’re flooring three bedrooms, each 5 m long and 4 m wide, with laminate. Coverage is 2.23 m² per box. Waste factor is 10%. Underlayment roll covers 15 m². Trim piece is 2.4 m long. One door per room, 0.9 m wide. Costs: $35 per box, $25 per underlayment roll, $12 per trim piece, $3 per m² adhesive, $15 per m² labor.
Room area: 5 × 4 = 20.00 m²
Total area: 20 × 3 = 60.00 m²
Room perimeter: 2 × (5 + 4) = 18.00 m
Total perimeter: 18 × 3 = 54.00 m
With 10% waste: 60 × 1.10 = 66.00 m²
Boxes: ⌈66 ÷ 2.23⌉ = 30 boxes
Area per plank: 1.20 × 0.19 = 0.228 m²
Pieces per box: ⌊2.23 ÷ 0.228⌉ = 10 planks
Total planks: ⌈66 ÷ 0.228⌉ = 290 planks
Underlayment rolls: ⌈60 ÷ 15⌉ = 4 rolls
Trim length (one door per room): 54 − (3 × 0.9) = 51.30 m
Trim pieces: ⌈51.30 ÷ 2.4⌉ = 22 pieces
Flooring cost: 30 × $35 = $1,050
Underlayment cost: 4 × $25 = $100
Trim cost: 22 × $12 = $264
Adhesive cost: 66 × $3 = $198
Labor cost: 60 × $15 = $900
Total: $2,512
Cost per m²: $41.87
Thirty boxes for three bedrooms, four rolls of underlayment, and 22 trim pieces. The plank count of 290 is a useful reference for staging the install and ordering from a single dye lot.
Ten flooring types load their own coverage and plank dimensions, which saves hunting through product data sheets.
Rectangle, L-shape, and direct area modes cover most room layouts without needing to split the calculation by hand.
Waste is applied to flooring only, and underlayment is calculated from bare area, matching how each material is actually ordered.
Trim is derived from perimeter with door widths deducted, which captures the most-forgotten line item on a flooring job.
Piece counts for plank and tile are reported alongside box counts, useful for layout planning and staging.
Metric and imperial units switch and convert every entered value, including cost per area.
Sixteen currencies and separate cost lines for flooring, underlayment, trim, adhesive, and labor give a real budget figure.
All math runs in your browser. Room dimensions and prices stay private.
Divide the room area with waste by the coverage per box. A 30 m² room with 10% waste needs 33 m² of flooring. At 2.23 m² per box, that’s 15 boxes.
Ten percent for most installs. Straight lay in a simple room can drop to 5 to 8 percent. Diagonal, herringbone, and complex rooms push waste to 15 to 20 percent.
Measure the longest length and widest width to the walls, not to the baseboard. For irregular rooms, split into rectangles or use the L-shape mode in this calculator.
Underlayment covers the bare room area without waste. A 60 m² floor needs 60 m² of underlayment. Divide by roll coverage to get the number of rolls.
Add up the perimeter of every room, subtract door widths, then divide by the length of one trim piece. A 54 m perimeter with three 0.9 m doors gives 51.3 m of trim.
Laminate has a wood-fiber core and a photographic top layer. LVP is entirely synthetic and waterproof. Both install as floating floors. LVP covers a similar area per box but handles moisture better.
Depends on tile size and box weight. A box of 30 cm ceramic tile usually holds 10 to 12 pieces. A box of 60 cm porcelain often holds 4 pieces. Coverage per box is the number that matters for ordering.
No. Underlayment is pieced edge to edge and doesn’t need pattern waste. Add a small buffer for cuts if the room is complex, but 0 percent is fine for most layouts.
The tool handles flat rooms. Stairs need a separate calculation for treads, risers, and stringers. Route to a stair flooring calculator for those.
Enter the same room dimensions and switch materials. The cost per square metre output shows the true comparison, including underlayment, trim, and labor.
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