Advanced options
Carpet comes on 4m and 5m wide rolls, so you buy a full-width cut: waste is normal and seams are best avoided in small rooms. Add underlay and gripper to the budget; both matter more to comfort and lifespan than an extra pound on the carpet itself.
What The Carpet Calculator Works Out
- Room area: length x width in square metres, the figure underlay and fitting are priced on. Measure the longest dimensions, including into the door threshold and any alcoves or bay windows, since the carpet tucks into them from the main piece.
- Carpet to order: a full-width cut from a 4m roll (or 5m if the room is wider than 4m) by the room's longer dimension plus 10cm trim, because carpet is sold by the roll width rather than the room's neat area. A 4 x 3.5m room (14 m2) needs a 4m-wide cut 4.1m long, 16.4 m2 bought. Rooms wider than 5m in both directions need a seam.
- Estimated costs: the carpet bought x your price per m2, plus underlay at about GBP 6 per m2 and fitting at about GBP 4 per m2 on the room area. Underlay does more for comfort, warmth and the carpet's lifespan than upgrading the carpet a grade, and old underlay is rarely worth keeping.
- Quality shorthand: 80/20 wool-twist mixes wear well in busy rooms, polypropylene shrugs off stains and suits stairs and families, and the showroom test is pressing a thumb in and watching how fast the pile recovers.
- Roll width (advanced): force a 4m, 5m or 3.66m (12ft) roll if you know what the carpet you want comes on. Choosing a 4m roll for a 4.2m-wide room shows you the two-cut seamed alternative and its extra waste.
- Trim allowance and pattern repeat (advanced): change the 10cm trimming allowance, and add the pattern repeat for patterned carpets, which need a whole extra repeat on the length so the design can be positioned in the room.
- Underlay and fitting prices (advanced): edit the GBP 6 and GBP 4 per m2 assumptions to match quotes. Good PU foam underlay is GBP 5 to GBP 8 per m2, fitting GBP 3 to GBP 6, often with a minimum charge for small rooms.
- Offcut waste (advanced): the difference between what you buy and the room area, as square metres and a percentage, and whether a seam is needed. Fitters place seams across traffic rather than along it.
- Gripper and door bars (advanced): 1.52m gripper rods for the room perimeter less one doorway, plus a door bar for each doorway.
- Stair carpet and total (advanced): each straight step takes about 50cm of carpet (tread plus riser plus tuck) at a 1m width, more for winders, and the total card adds carpet, underlay and fitting for the room and stairs together.