Carpet Calculator
Carpet calculator — enter a room’s length and width and a waste allowance to get the carpet area you should order, in square metres, square feet and square yards. Includes the offcut and matching wastage that real installs need. Runs in your browser.
Carpet Calculator
How to Use the Carpet Calculator
Measure the room
Enter the longest length and widest width in metres.
Set the waste
10% for plain; more for patterns or stairs.
Read the order area
See the area to order in m², ft² and yd².
Match the quote
Compare against your supplier in their unit.
Ordering Carpet Without Coming Up Short
Carpet is one of the easier materials to under-order, because the floor area you measure is never the amount you actually need to buy. Every installation loses material to trimming along the walls, to seams where strips join, to doorway transitions, and — on patterned carpet — to matching the design across those joins. This calculator takes your room’s length and width, adds a waste allowance for all of that, and reports the area you should order in square metres, square feet and square yards, so you can compare like-for-like with whatever unit your supplier quotes in.
The waste allowance is the part that matters most. A plain, rectangular room is well served by around ten percent over the bare floor area. A patterned carpet needs more — fifteen percent or higher — because each strip has to be shifted to line the pattern up, and that shift is wasted material. Stairs, hallways, and rooms full of alcoves and angles push the figure higher again. The guiding principle is simple: the cost of a little extra carpet is trivial next to the cost and delay of running short halfway through fitting, when matching a new batch may be impossible. Round up rather than down.
One practical complication this estimate flags but cannot fully resolve is roll width. Broadloom carpet is manufactured in fixed widths — commonly around 3.66 metres or 4 metres — and if your room is just wider than the roll, the fitter must add a second strip and a seam, which can waste far more than the headline percentage suggests. The area-plus-waste number here is the right figure for budgeting and for sanity-checking a quote, while a professional on-site measure will confirm exactly how the roll width and any pattern repeat affect the real cut. Remember too that underlay is bought to the same floor area, and that stairs are measured separately, tread plus riser per step. Measure the widest points of the room, never stretch a measurement to be optimistic, and let the waste allowance do its job. As with every RECATOOLS tool, the calculation happens entirely in your browser, so your measurements never leave your device.
The floor area is never the order quantity — trimming, seams and pattern matching mean you always buy more than you measure.
10 Facts About Carpet
Carpet is often sold by the square yard or square metre.
Broadloom carpet comes in fixed roll widths (often 3.66 m / 4 m).
A 10% waste allowance is typical; more for stairs or patterns.
Patterned carpet needs extra for matching repeats.
Roll width can force waste if the room is slightly wider.
1 m² ≈ 10.76 ft² ≈ 1.196 yd².
Underlay is bought to the same area as the carpet.
Stairs typically add extra metres per flight.
Always measure the widest points of the room.
This calculator runs in your browser — nothing is uploaded.
Frequently Asked Questions
- Start with the floor area — length times width — then add a waste allowance for offcuts, trimming and pattern matching. This calculator does both and shows the result in square metres, square feet and square yards so you can match whatever unit your supplier quotes in. A 10% allowance is a sensible default for a plain rectangular room.
- No install uses carpet perfectly. You lose material to trimming along walls, to seams, to doorway transitions, and to matching a pattern across a join. Ordering only the exact floor area almost guarantees coming up short. Ten percent covers a simple room; add more for patterns, stairs, or awkward shapes.
- About 10% for a plain rectangular room, 15% or more if the carpet has a pattern that must be matched, and extra again for stairs, hallways and rooms with many alcoves or angles. When in doubt, round up — the cost of a little extra carpet is far less than the cost and delay of running short mid-install.
- Broadloom carpet is made in fixed roll widths, commonly around 3.66 m (12 ft) or 4 m. If your room is just wider than the roll, you may need a second strip and a seam, which increases waste well beyond the simple area. This tool gives the area-plus-waste figure; your fitter will confirm how the roll width affects the actual cut.
- One square metre is about 10.76 square feet and about 1.196 square yards. Carpet is sold by the square metre in much of the world and historically by the square yard in the US and UK trade, so the calculator shows all three to avoid conversion mistakes when comparing quotes.
- Yes, broadly — underlay is bought to cover the same floor area as the carpet, though it has its own roll widths and a smaller waste factor since it does not need pattern matching. Use the floor-area figure (before heavy pattern waste) as your underlay estimate.
- Stairs are measured separately, as each step needs the tread depth plus the riser height in carpet, and a flight adds up quickly. A rough rule is to allow extra running length per flight. For an accurate stair figure, measure one step’s tread plus riser and multiply by the number of steps, then add to your room total.
- Always. Measure the longest length and the widest width of the room, including into doorways and alcoves you want carpeted. Carpet cannot be stretched to fill a gap, so under-measuring is the costly mistake. It is safer to measure generously and let the waste allowance absorb the rest.
- It is a reliable ordering estimate for a rectangular room. Irregular shapes, roll-width seams, pattern repeats and stairs all affect the true cut, which a professional fitter will finalise from an on-site measure. Use this figure to budget and to sanity-check a supplier’s quote.
- Completely free, with no account or limit. It works offline once the page has loaded and collects no data.
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