Carpet Calculator
Estimate linear carpet length for a rectangular room from the available roll width.
Last reviewed September 19, 2026
Result
26 ftEstimate
The rectangular offcut is already visible in purchased area. Pattern repeat, pile direction and seam placement may require extra length.
- Full-width strips
- 2
- Carpet area purchased
- 312 ft² (34.67 yd²)Estimate
- Room area
- 195 ft² (21.67 yd²)
https://calcgallery.com/flooring-tile/carpet-calculator/
Results are estimates for planning only. Actual needs vary with site conditions, products and workmanship. Always confirm quantities with your supplier and follow local building codes and manufacturer instructions. Read the full disclaimer
How to use it
- Enter the length and width of one rectangular room.
- Enter the usable width of the carpet roll offered by the supplier.
- Compare the strip count and purchased area with the room area.
- Use the linear length as a starting quantity and confirm seam direction with the installer.
How it is calculated
Carpet is sold by linear length from a fixed-width roll. The calculator checks both ways of turning the room:
Layout A = ceil(room width ÷ roll width) × room length
Layout B = ceil(room length ÷ roll width) × room width
Linear order = smaller of A and BPurchased area is the chosen linear length multiplied by roll width. It makes the geometric offcut visible instead of hiding it in a percentage.
Layout limits
The shortest rectangular layout is not always the correct installation. Pile direction, daylight, doorways and acceptable seam positions can require the other orientation.
Confirm seams before buying. Avoid high-traffic seam locations and follow the carpet manufacturer’s requirements.
Allow for pattern repeat. Patterned carpet must align across adjacent strips. That can materially increase the cut length.
Measure the widest points. Rooms are rarely perfectly square. Use the maximum length and width, including recesses that must be covered.
With your numbers
- Layout A = 2 strips × 15 ft
- Layout B = 2 strips × 13 ft
- The shorter layout uses 2 strips and 26 ft of carpet
Quick reference
The rectangular offcut is already visible in purchased area. Pattern repeat, pile direction and seam placement may require extra length.
| Job | Linear carpet to order |
|---|---|
| 12 × 12 ft room, 12 ft roll | 12 ft |
| 15 × 13 ft room, 12 ft roll | 26 ft |
| 18 × 10 ft room, 12 ft roll | 18 ft |
| 20 × 14 ft room, 12 ft roll | 28 ft |
| 4 × 4 m room, 4 m roll | 4 m |
| 4.5 × 4 m room, 4 m roll | 4.5 m |
Common questions
- How much 12 foot carpet is needed for a 15 by 13 foot room?
- The better rectangular layout uses two 13 ft strips, so the order is 26 linear ft of 12 ft-wide carpet, or 312 ft² purchased.
- Why is purchased area larger than room area?
- Carpet comes at a fixed roll width. Every strip is full width, so the part beyond the room edge becomes an offcut.
- Does this include pattern matching?
- No. Pattern repeat and pile direction can add length to every strip. Use the manufacturer’s repeat and an installer’s seam plan for patterned carpet.
- Can I calculate several rooms together?
- Not reliably with this page. Doorways, roll direction and reusable offcuts connect the layouts. Calculate rooms separately, then have the combined cutting plan checked.