Carpet Quantity Calculator for Broadloom & Carpet Tiles
Enter your room and carpet details — get a precise ordering specification, including wastage, seams and pattern matching.
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Carpet Specification
How to Use This Carpet Calculator
- Choose Metric or Imperial to set your working units.
- Select Broadloom (roll) or Carpet Tiles.
- Enter your room length and width.
- For broadloom, enter the roll width; for tiles, enter the tile size.
- Choose Plain, Patterned, or Custom wastage, entering a pattern repeat if your carpet has one.
- Click Calculate for your total length or area, seams, and quantity to order.
Understanding Broadloom, Seams and Pattern Matching
Broadloom carpet comes on a continuous roll, typically 3.66–5m wide. If your room is wider than the roll, it needs to be seamed together from multiple strips — each strip runs the full length of the room, and the number of strips (and therefore seams) is set by dividing the room width by the roll width.
For patterned broadloom, every strip's length is rounded up to the next full pattern repeat, so the design lines up cleanly across every seam — the same principle used for wallpaper drops, since both are continuous rolled goods cut into parallel strips.
Carpet tiles are calculated differently — as a flat area, divided by the tile size, the same way as floor tiles, with an extra allowance if the tiles are patterned.
Worked Example: Broadloom for a Mid-Sized Room
Take a 500cm × 400cm room with plain broadloom on a 4m-wide roll. Since the room's 4m width matches the roll width exactly, only one strip is needed — no seams at all. At 10% wastage, the total length to order comes to 5.5m, covering 22m² of floor.
Frequently Asked Questions
How much carpet do I need for a room?
It depends on whether you're using broadloom (roll) carpet or carpet tiles, your room dimensions, the roll width, and whether the carpet is patterned. Use the calculator above with your own measurements for an exact quantity, including seams and wastage.
What is a carpet seam and why does it matter?
A seam is the join between two strips of broadloom carpet, needed whenever the room is wider than the roll. Fewer seams generally means a cleaner, more expensive-looking installation, so the number of seams is worth knowing before you commit to a roll width.
What's the difference between broadloom carpet and carpet tiles?
Broadloom is a continuous roll, typically 3.66–5m wide, cut into strips and seamed together to cover a room. Carpet tiles are modular squares laid individually, calculated by area and box quantity in the same way as floor tiles.
How does pattern repeat affect carpet quantity?
For patterned broadloom, each strip's length is rounded up to the next full pattern repeat so the design lines up across every seam, which uses more carpet than a plain flat-area calculation.
What's the standard wastage allowance for carpet?
A flat 10% is the standard allowance for cuts and joins on plain broadloom. Patterned or bespoke carpet typically needs more, either from the pattern-repeat rounding on broadloom or an additional allowance for motif alignment on carpet tiles.