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Carpet calculator: how much carpet do I need?

Put in your room sizes and stairs. The calculator works out which roll width to buy, how many metres to order, where any seams go and how much is wasted, with a cut plan showing every piece on the roll.

Your rooms

Length and width of each room at its widest points. Metres, centimetres or feet and inches all work: 3.8, 380cm or 12'6". For a hall or landing, give the length as measured over the stair nose: that's the way its pile runs.

Along the length

Stairs

Roll widths to compare

You need

6.70 m of 5 m wide carpet (33.50 m²)

No joins · 10% waste · 30.12 m² of floor

Tap a roll width to see its cut plan.

Cut plan

5 m roll widthHall1.10 × 4.10Stairs0.90 × 2.00steps 1–4Lounge3.80 × 5.20Stairs0.90 × 1.50steps 11–13Stairs0.90 × 1.50steps 8–10Stairs0.90 × 1.50steps 5–76.70cut m6.70 m off the roll · pile runs down ↓red = cut · dashed = roll edge · across × along

Fitters: save this job, add your prices and send the customer a quote with FitterMate. Try it free for 14 days

The 5 m roll runs across the top and unrolls down the page, so the pile points down. Each colour is one room.

Fitters: plan the whole job, then quote it

FitterMate adds winders, L-shaped rooms and bays, pile direction, sheet vinyl, LVT packs, your own prices, and a quote your customer can sign.

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How carpet is sold

Carpet comes off a roll, usually 4 m or 5 m wide in the UK, and some ranges in other widths. You buy a length of the full roll width, so you pay for the width of the roll, not just the floor area. A room 3.8 m wide cut from a 4 m roll wastes a 20 cm strip down one side. The same room from a 5 m roll wastes 1.2 m. That's why the right roll width matters more than the square metres.

Seams

If a room is wider than the roll in both directions it needs a seam (a join). Seams are best kept out of doorways and the busiest walkways. The calculator chooses the fewest seams first, then the least carpet. The cut plan shows where each piece comes from.

Pile direction

Carpet has a pile that leans one way along the roll, and it looks a different shade from each direction. Every piece in one room has to run the same way, or a join shows. On stairs the pile always runs down the stairs, and in halls and landings it runs the same way, over the stair nose, so their length is measured that way. In other rooms you can choose, or let the calculator pick the cheapest way. The calculator keeps to both rules, which is why it won't always cut a piece the way that looks cheapest.

Stairs

Count the treads (the parts you step on) from the bottom to the top. Measure the width of the stair where the carpet will go. Each step needs enough for the tread, the riser and the nosing, and the flight is cut along the roll so the pile runs down. Turning steps (winders) take more carpet and are cut on their own. The full FitterMate planner handles those.

Measuring a room

  • Measure the full length and width at the widest points, into alcoves and bay windows.
  • Measure into the doorway, to where the carpet will finish under the door.
  • L-shaped rooms: put in the overall length and width. The cut-out is waste, but the room still has to come off the roll in one piece unless you're happy with a join.
  • This is a guide. Have your fitter measure up before you order, as they're the one cutting it.