Carpet Calculator — m to m², rolls, cost
How to use this calculator
Enter room dimensions in meters or centimeters. Select carpet roll width (3.66 m or 4.57 m standard metric widths). The calculator computes linear meters off the roll, seams, padding, and gripper rod perimeter.
Roll widths — 3.66 m (12 ft equiv.) or 4.57 m (15 ft equiv.).
Underlay — same area as carpet. Gripper rods run the room perimeter minus doorways.
Saved Calculations
| Time | Shape | Area m² | Carpet m² | Roll m | Seams | Cost |
|---|
How to Calculate Carpet (Metric)
Broadloom carpet is supplied off a continuous roll in fixed widths — commonly 4 m or 5 m in Europe, here set to 3.66 m and 4.57 m to mirror the imperial 12 ft / 15 ft goods. Order quantity depends on how many full-width strips run the room length, so a room slightly wider than the roll still pulls a second strip and creates a seam. Pile direction is held constant across strips, matching how a fitter orders cut-length carpet rather than nesting offcuts.
How to use
Choose the room shape, enter dimensions in m/cm/mm (or floor area plus perimeter on the Custom tab), and pick the roll width your supplier stocks. Use 5% waste for a single seamless strip, 10% for a typical multi-strip room, 15% for repeat-matched patterned carpet. Open Cost for carpet, underlay and gripper-rod pricing in your currency, and Installation for labour per m².
Formulas
strips = ceil(room width ÷ roll width). seams = strips − 1. linear m = strips × room length × (1 + waste). carpet m² = strips × roll width × room length × (1 + waste). Underlay = floor area (m²). Gripper rod = perimeter − 0.9 m per doorway.
EN standards & related work
EN 1307 classifies textile floor coverings by use class (21–23 domestic, 31–33 commercial); EN 14499 covers carpet underlay durability and EN 16354 underlay performance — match the class to expected traffic. For a hard-surface option compare the flooring calculator (packs & cost); price wall finishes with the paint calculator or tile & grout calculator.
On install day
2025 EU/UK numbers to sanity-check a quote: residential broadloom €20–55/m² (£18–50/m²), underlay €4–8/m², gripper rod €1.50–2.50/m, fitting €8–18/m² depending on furniture removal and uplift of the old carpet. The #1 estimator miss is running carpet across the room's short axis to "save a strip" — you trade one seam for an off-pile that shows up in the first month of vacuuming. Order a few extra metres of gripper rod for closets and bay windows, and check the underlay use-class against EN 16354 (PT2 minimum for living rooms, PT4 for hallways and stairs). Stairs are billed per step, not per m² — count them separately.
FAQ
Why is carpet ordered above floor area? You buy full roll-width strips, so a room narrower than the roll still consumes the whole width — the surplus is unavoidable trim. Why wider rolls? A 4.57 m roll covers most rooms seamlessly, and seams are the first place pile wears. Pattern match? Add 10–15% so the repeat aligns across every seam. Walls too? See the drywall calculator or the brick wall calculator.
