Carpet Quantity Calculator
Estimate carpet roll length from room dimensions, roll width, seam allowance and cutting waste. Compare the two practical roll orientations before purchasing material.
Carpet inputs
Carpet requirement
How carpet quantity is calculated
Because carpet is normally supplied at a fixed roll width, the number of strips needed across the room controls the linear quantity.
Base length = strips × room run + seam allowance
Planning length = base length × (1 + waste)
Worked example
For a 5.5 × 4 m room and 4 m wide carpet, one strip can span the 4 m room width and run 5.5 m. If the installation direction requires that arrangement, the starting material is about 5.5 linear metres before the entered allowance.
Why seams matter
A room wider than the roll often requires multiple strips. Their seams need planning, and patterned carpet can need the second strip to begin at a matching point rather than simply at the room boundary.
Pattern repeat can change the answer
Geometric or directional carpet may require additional material so adjacent lengths can be aligned. This should be calculated from the manufacturer's pattern-repeat information rather than a generic percentage.
Limitations
The model assumes a rectangular room and uniform roll width. It does not optimize irregular room geometry, stair layouts, multiple rooms, pattern matching or seam placement in detail.
Frequently Asked Questions
Does carpet roll width affect quantity?
Yes.
Can I compare two orientations?
Yes.
Why add waste?
For cuts, trimming and unusable remnants.
Does pattern matching require extra?
It can.