Carpet Calculator
Estimate carpet from physical roll width, strip direction, seams, and linear yardage—not area divided by nine.
- Room area
- 252 ft²
- Best straight-strip length
- 28 ft
- Length with allowance
- 30.8 ft
- Approximate seams
- 1
This compares two straight strip orientations. Pattern repeat, pile direction, door seams, room joins, and usable offcuts require a measured carpet plan.
Show calculation
min(ceil(14 ÷ 12) × 18, ceil(18 ÷ 12) × 14) × 1.1 ÷ 3 = 10.27 ydTransparent method and editable product assumptions. Verify current labels and project requirements.
How this calculator works
The room is tested in both axis-aligned directions. In each orientation, the number of full roll-width strips is rounded first, then multiplied by the cut length.
The shorter straight-strip plan becomes the base linear footage. A user-entered allowance covers trimming and simple matching before conversion to linear yards.
A professional seaming plan may choose the other orientation to keep seams away from traffic, doors or light. Patterned carpet and connected rooms need repeat-aware cuts.
Formula
Linear yards = min[ceil(width ÷ roll width) × length, ceil(length ÷ roll width) × width] × allowance ÷ 3The live result shows the selected straight-strip length.Control example: 18 × 14 ft room
A 12 ft roll needs two 18 ft strips in one direction or two 14 ft strips in the other.
The shorter plan is 28 ft. With 10% allowance: 30.8 ft ÷ 3 = 10.27 linear yards.
Assumptions and limits
- Measure finished room dimensions and confirm the exact carpet roll width, pattern repeat, pile direction and seam-placement requirements.
- Measurements describe one simple project geometry.
- Waste and package values are editable planning assumptions.
- It is a two-direction approximation, not a multi-room seam plan, pattern-match optimizer, stair takeoff, or installation quote.
Common measuring mistakes
- Mixing nominal dimensions with actual installed coverage.
- Skipping whole-package or stock-length rounding.
- Failing to verify the page’s stated measurement and product assumptions.
- Using a planning estimate outside the limitations stated on this page.
Sources
Product-specific values remain editable. These sources support the method and stated examples; they are not a universal substitute for your supplier’s current label.
- CRI carpet installation standard overview Treats seam placement, pile direction and installation method as project-specific requirements.
- The Home Depot carpet measuring guide Explains room measurement and the effect of carpet roll layout and waste.
Questions people ask
What does the Carpet Calculator calculate?
Calculate carpet linear yards by comparing two straight room layouts against the selected carpet roll width and waste allowance.
How does this carpet calculator work?
Linear yards = min[ceil(width ÷ roll width) × length, ceil(length ÷ roll width) × width] × allowance ÷ 3
Which measurements should I enter?
Measure finished room dimensions and confirm the exact carpet roll width, pattern repeat, pile direction and seam-placement requirements.
Does the estimate include every project requirement?
No. It is a two-direction approximation, not a multi-room seam plan, pattern-match optimizer, stair takeoff, or installation quote.
Can I use metric measurements?
Yes. Switch to Metric above the form. The calculator converts the displayed measurements while keeping the same geometry and whole-item rounding.