Carpet Calculator
Enter your room dimensions and roll width to get linear feet, seams, and square yards -- the units carpet is actually bought and installed in.
Carpet to purchase
35.2 sq yd
(317 sq ft)
Linear feet from the roll
26.4 ft
Seams
1
Padding needed
21.0 sq yd
Total cost
--
At the defaults above (a 12x15 ft room, 12 ft roll, no pattern repeat) that's 2 strips with 1 seam, 26.4 linear feet off the roll, and 35.2 sq yd (316.8 sq ft) of carpet to buy.
How it's calculated
When a room is wider than the roll, the calculator splits it into full-width strips run along the room's length, adds the waste percentage (10% by default, higher if you pick a patterned carpet with a repeat to match), and converts the resulting linear footage to square yards at the roll's width -- the same method carpet retailers use to quote material. Padding and installation labor are priced separately, against the room's actual footprint rather than the waste-inflated material purchase.
Keep going
- Comparing carpet against a hard-surface floor for the same room? The flooring calculator prices that option by the box instead of the roll. Flooring Calculator
- An oddly-shaped room's real area feeds directly into how many strips and seams a carpet job needs -- work that out here first. Square Footage Calculator
Frequently Asked Questions
Why is carpet sold by linear feet from a roll, not by the square foot directly?
Broadloom carpet comes off a roll at a fixed width -- 12 ft is the standard US width, 15 ft is a common second option -- so a strip cut to your room's length uses that full roll width even if your room is narrower, which is what "linear feet" is measuring.
What's a seam, and does it matter?
A seam is where two strips of carpet are joined because the room is wider than one roll. Seams are visible up close and are best planned away from high-traffic paths or placed under furniture; this calculator tells you how many a given room and roll width will need.
Why does padding use a different waste percentage than the carpet itself?
Padding is cut directly to the room's real footprint -- it doesn't need to match a fixed roll width or carry seam waste, so it typically uses a smaller waste allowance (5% here) than the face carpet (10% here).
Should I pick a 12 ft or 15 ft roll?
A wider roll (15 ft) can cover a wider room with fewer or no seams, which often looks better in an open space, but not every carpet style is milled at 15 ft. Check what width your chosen carpet is actually available in before assuming 15 ft is an option.
Does the installation cost include removing old carpet?
No -- the installation cost field here is a flat rate per square yard of new carpet installed. Old carpet removal and haul-away is commonly a separate line item; ask your installer whether it's included.
What is pattern repeat, and why does it change the waste percentage?
It's how far a pattern has to travel before it repeats itself. A solid or textured carpet has no repeat to match, so it only needs the standard waste allowance; a patterned carpet has to be cut so the pattern lines up strip to strip, which wastes more material at every seam -- more for a large, bold repeat than a small one. Picking a tier above sets a higher default waste percentage, which you can still fine-tune in the waste field.