Guide · For the trade
Pattern match carpet: the repeat, the match types and how we order it so the seams line up
Pattern match carpet is any broadloom with a repeat that has to line up across a seam, and the repeat is the two numbers on the spec sheet, width by length, such as 12 by 10 inches or 36 by 33 inches. Matching costs yardage: every drop is cut to a whole number of repeats plus one extra repeat, which adds 5 to 20 percent to a plain-carpet estimate, more for a large repeat and a room with many seams. The match type, straight (set), half-drop or quarter-drop, decides how the drops are offset against each other, and the installer needs the seam diagram, the repeat and the match type before the first cut.
This guide is for the designer or the junior ordering a patterned broadloom and wanting to know what the repeat does to the quantity and the install. It covers the repeat line, the match types, the yardage arithmetic, bow and skew, what the order has to say, and what to tell the installer. The patterned carpet guide covers choosing the pattern; this one covers getting it on the floor in one piece.
Reading the pattern repeat on a spec sheet
The repeat is the distance before the design repeats itself, across the width and along the length. A wool Wilton loop with a 3.94 by 4.33 inch repeat has a motif under 5 inches square; a woven jacquard at 43 by 45 5/8 inches has a repeat the size of a side table. Hand-loomed and flatwoven lines often list a repeat in one direction only, or "random" for a texture, and those need no matching beyond keeping the pile direction consistent. The length repeat drives the yardage, because carpet is cut along the roll; the width repeat is why a patterned carpet is never filled with a piece turned sideways.
Straight match, half-drop and quarter-drop
| Match type | How the drops line up | What the installer offsets | Yardage effect |
|---|---|---|---|
| Straight (set) match | The motif sits at the same point on every drop; the pattern reads straight across the seam | Nothing; the drops start at the same point in the repeat | One extra repeat per drop |
| Half-drop match | Each drop is offset by half the length repeat, so the motif staggers like brickwork | Every other drop by half a repeat | One and a half extra repeats per drop |
| Quarter-drop match | Each drop is offset by a quarter of the repeat; the motif steps diagonally | Each drop by a quarter repeat more than the last | Up to two extra repeats per drop |
| Random or no match | Textures, random loops, most hand-loomed and flatwoven lines | Only the pile direction | None; estimate as a plain carpet |
The spec sheet usually names the match after the repeat: a Couristan hand-loomed wool loop lists "1 by 4 inches, half-drop match". When the sheet gives a repeat and no match type, we confirm with the mill before the order.
How pattern match carpet adds to the yardage
Plain carpet is estimated by laying out the drops, each one the room length plus 3 inches. Pattern match carpet rounds each drop up to whole repeats and adds one more so the installer can slide the drop to match its neighbor. A 14 ft room in a 36 inch length repeat takes a 15 ft drop of plain carpet; in pattern it takes 168 inches rounded up to five repeats, 180 inches, plus one repeat, 216 inches, which is 18 ft per drop. Over four drops that is 12 extra feet of roll, about 16 square yards on top of 80, roughly 20 percent. A 4 inch repeat on the same room adds under 5 percent; a half-drop match adds another half repeat to alternate drops. Stairs count the same way per step: a 20 inch step takes the next whole repeat above 20 inches. The carpet yardage guide has the plain-carpet arithmetic this sits on top of, and we run the pattern estimate from your plan before the order.
Pattern bow, skew and run-off
No pattern comes off a loom or a tufter perfectly square. Bow is the pattern curving across the width; skew is the pattern running at a slight angle to the edge; run-off is the repeat measuring slightly longer on one roll than another. Mills work to a tolerance of about 1 inch of bow or skew across the width and a small percentage of elongation along the length, which is why the whole job is ordered in one dye lot and, where the mill can cut it, one roll. The installer corrects what the mill allows by power-stretching and stay-nailing the drop; the honest conversation with the client is that a 36 inch repeat over a 30 ft room will have a seam that matches to within 1/4 inch, not to zero. The dye lots guide covers the ordering side.
What the order has to say
- The style, color and dye lot requirement: whole job from one dye lot, one roll where possible.
- The repeat and the match type as the spec sheet gives them, so the mill cuts to the repeat and the installer is not guessing.
- The seam diagram, with every drop drawn in whole repeats plus one, the pile direction, and the seams placed away from the main light source where the room allows.
- The start point: which motif lands where, usually centered on the doorway or the fireplace.
- The stairs and halls as separate cuts, each in whole repeats.
We produce the seam diagram and the pattern estimate from your plan and send them with the quote; the seam diagram guide shows what it looks like, and the ordering broadloom guide covers the rest of the order.
What to tell the installer
That the carpet is a pattern match, with the repeat and the match type on the work order. That every drop is cut to the diagram with the extra repeat left at the end of the drop. That the drops are dry-laid and matched before any seam is sealed, and the carpet is power-stretched, not knee-kicked, because a kicker will not hold a match across a 12 ft width. And that a mismatch of more than 1/4 inch at a seam is a stop-work call to us, not something to cut around. On a patterned stair runner each step is cut so the motif lands at the same point on every tread; the patterned stair runner guide covers it.
Questions designers ask
What is a drop match carpet?
A pattern whose drops are offset by a fraction of the length repeat, half for a half-drop and a quarter for a quarter-drop, so the motif staggers across the room rather than lining up in rows. It takes up to half a repeat more yardage per drop than a straight match.
How much extra carpet does pattern matching take?
One extra repeat per drop plus rounding each drop up to whole repeats: under 5 percent for a repeat of a few inches, 10 to 20 percent for a 24 to 36 inch repeat, more for a half-drop match. We run the exact number from your plan before the order.
What happens if the pattern does not match at the seam?
Within 1/4 inch is the realistic standard on a large repeat. Beyond that it is a cutting error, a stretching error or mill run-off, and the installer stops and calls before sealing the seam; if the carpet is at fault we take it up with the mill.
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