YepCalc

Carpet Calculator

Find how much carpet to buy for a room and what it costs. Enter each room's length and width and choose the roll width to see the cuts, the seams, and the length to order. Add prices for carpet, pad, and installation to estimate the total. For laminate, vinyl plank, or hardwood sold by the box, use the Flooring Calculator.

Section 1

Add each room or rectangular part of a room. Subtract areas without carpet, such as a hearth; they reduce the floor area, not the carpet.

Roll width

Choose a roll width

Direction

Choose the carpet direction

Pile must run the same way across a room. If you split a room into sections, choose Along the length or Along the width, and enter each section's Length in the same direction.

Pattern and trim

Use the length repeat from the product details. Leave it blank for plain carpet.

Choose the pattern match

Check the pattern match in the product details.

Default: 6 in (3 in at each end)

Extra length on each cut for trimming at the walls.

Cost

Pad, also called underlay, is priced on the floor area.

Installation is priced on the floor area. Leave it blank if the carpet price includes it.

Result

Enter the dimensions of a room to see the carpet you need.

How much carpet you need

Carpet is cut from a roll of a fixed width and sold by the length, so you order a roll width and a length rather than an area. The UK retailer Flooring Hut notes that the roll width has a direct effect on how much carpet you need. The calculator lays full-length cuts side by side in each section:

Cuts = width across the cuts ÷ roll width, rounded up

Cut length = length along the cuts + trim allowance

Carpet length = cuts × cut length, added up for all sections

Carpet to buy = roll width × carpet length

Each cut runs the full length of the section, and the seams run along the cuts, so a section with 2 cuts has 1 seam. The Carpet and Rug Institute's CRI 105 installation standard says to keep seams to a minimum and run them the length of the area. The total seam length is shown so you can check how much seam tape you need.

With Least carpet, the calculator tries the cuts both ways in each section and uses the one that needs less carpet. If both need the same length, it uses the one with fewer seams, and then the one along the Length. CRI 105 also lists economic use of material as one of the factors for the carpet direction. Pieces of the same carpet next to each other need the pile running the same way, so for one room split into sections, choose Along the length or Along the width.

The calculator doesn't add a waste percentage. The part of the cuts you trim off and don't use is shown as Offcuts and trim, the carpet to buy minus the floor area. Flooring Hut advises planning the carpet against the roll width rather than adding a fixed percentage to the floor area.

A section you subtract, such as a hearth, reduces the floor area used for the pad and installation, but not the carpet. The cuts still run from wall to wall, and the part over the hearth becomes an offcut. For a room that isn't a rectangle, such as one with a curved or angled wall, enter the rectangle that encloses it.

Carpet roll widths

Roll width Where Examples
12 ft Standard in the US Mohawk Everstrand Revive, Tarkett Pinnacle
15 ft US, for some carpets Mohawk Everstrand Revive
3.66 m Standard in Australia and New Zealand, about 12 ft Godfrey Hirst Pegasus, Bremworth Te Aroha
4 m Common in the UK Cormar, as listed by Flooring Hut and Online Carpets
5 m UK, for some carpets Cormar, as listed by Flooring Hut and Online Carpets

A wider roll can avoid a seam. A room 14 ft wide needs 2 cuts and a seam from a 12 ft roll, but fits in one cut from a 15 ft roll. Some US carpets also come 13 ft 1 in wide. For that or any other width, choose Custom width and enter it in ft and in.

In Metric, the calculator starts at 3.66 m in Australia and New Zealand and at 4 m elsewhere, based on your browser's region. The two are easy to mix up, and a room just over 3.66 m wide needs a seam on one but not the other. In Canada, the calculator starts in Metric. Switch to US to choose the 12 ft and 15 ft rolls.

Pattern repeat and trim allowance

A patterned carpet needs extra length on each cut so the pattern lines up across the seams. The pattern repeat is the length before the pattern repeats, and the pattern match is how it lines up. Both are in the product details. The retailer Georgia Carpet notes that set match and half drop are the most common:

Pattern match Cut length
Set match length + trim allowance, rounded up to a whole number of repeats
Half drop match length + trim allowance + one repeat

With a set match, every cut starts at the same point of the pattern. The flooring estimating software Measure Square adds enough to each cut to reach the next full repeat, the same as the calculator. With a half drop match, the next cut starts half a repeat lower. The carpet maker Milliken says to cut drops one repeat plus 3 to 4 in longer than the area. The calculator adds the repeat even to a section with a single cut, so the pattern can line up with the next room. CRI 105 notes that patterned carpet needs extra material, and the repeat can vary slightly along a roll, so for a large pattern, check the amount with your retailer or installer.

The trim allowance is the extra length on each cut that's trimmed off at the walls. CRI 105 calls for at least 3 in at each wall, so the calculator starts at 6 in. The UK retailers Online Carpets and Flooring Hut add 10 cm, the metric default. The allowance is added only along the cuts, not across them, so a room 12 ft wide fits on a 12 ft roll, as US retailers lay it. When a room is almost as wide as the roll, there's little left to trim at the walls. Ask your installer, or choose a wider roll.

Examples

A room 20 ft × 14 ft

Along the width, the room takes 2 cuts of 14 ft 6 in, which is 29 ft of carpet. Along the length, it would take 2 cuts of 20 ft 6 in, which is 41 ft. So buy 12 ft × 29 ft of carpet, 348 ft² or 38.67 yd², with one 14 ft seam. The floor is 280 ft², so 68 ft² is offcuts and trim. From a 15 ft roll, the room fits in one cut of 20 ft 6 in, 307.5 ft², with no seam.

The cost with pad and installation

For the same room, carpet at $2.50 per ft², pad at $0.60 per ft², and installation at $1.00 per ft² cost 348 × $2.50 = $870 for the carpet, 280 × $0.60 = $168 for the pad, and 280 × $1.00 = $280 for installation. The total is $1,318. The pad and installation use the floor area, not the carpet you buy.

Metric dimensions

A room 4.5 m × 3.6 m fits in one cut from a 4 m roll. With 10 cm for trimming, buy 4 m × 4.60 m, 18.4 m², for a floor of 16.2 m². From a 3.66 m roll, it's 3.66 m × 4.60 m, about 16.84 m².

FAQ