Carpet Calculator: Square Yards, Square Feet & Roll Cut Estimator
Use this carpet calculator to calculate the exact square yards, square footage, and linear roll cuts needed to carpet any bedroom, basement, or full house. Commercial broadloom is manufactured in fixed 12-foot and 15-foot roll widths; this estimator factors in roll cutoffs, uniform pile nap direction, and carpet padding cushions.
Order 48 sq yds (432 sq ft) off a 12-ft broadloom roll (36 linear ft cut length). 1 field seam(s) required.
| Room Dimensions | 18 ft × 14 ft |
|---|---|
| Net Floor Area | 252 sq ft (28 sq yds / 23.4 sq m) |
| Broadloom Roll Width | 12 Feet Wide |
| Strips & Seams | 2 cut strip(s), 1 longitudinal seam (18 LF seam tape) |
| Total Ordered Carpet | 48 sq yds (432 sq ft) |
| Cutting & Seaming Allowance | 10% included |
| Underlayment Rebond Pad | 30 sq yds (~265 sq ft) |
| Estimated Material Cost (@ $28/sq yd) | $1,344 |
📐 Show Formula and Default Assumptions
We believe all home improvement estimates should be transparent and verifiable. Below is the exact math running in this browser tool:
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Square Yards = Total Square Feet ÷ 9.0 (1 sq yd = 9 sq ft) -
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Commercial Roll Width = Exactly 12 Feet (144") or 15 Feet (180") -
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All Room Seams Must Face the Primary Natural Light Source -
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Padding Square Yards = Carpet Net Square Yards (6-lb to 8-lb Rebond Pad)
Note: All default assumptions (waste %, coverage rates, container yields) can be adjusted directly in the input fields above to match your project specifications.
How to Measure Rooms for Broadloom Carpet and Seam Layout
- Measure room dimensions into doorways and closets: Always measure into the center of doorway thresholds where carpet seams transition to adjoining rooms.
- Account for fixed roll widths (12 ft vs 15 ft): If your room is 13 ft by 18 ft and you order a 12-ft roll, you will need a 1-foot fill seam running the entire 18-foot length.
- Keep pile direction consistent across all cuts: Carpet fibers have a natural grain lean called pile nap. If a seam joins two pieces running in opposite directions, the seam will look like two different color dyes.
- Add a 3-inch trimming margin to all edges: Walls are rarely perfectly square; ordering 3 inches extra on all sides prevents carpet fitters from falling short at bowed corners.
- Select premium 7/16-inch 8-lb rebond padding: Never skimp on carpet pad; a high-density 8-lb cushion extends carpet life by 50% and provides superior thermal insulation.
- Plan seams away from heavy foot traffic: Never locate a carpet seam perpendicular to an entry doorway; position seams along walls or under furniture.
How the Carpet Calculation Works (Worked Example)
Consider carpeting a family room 18 ft long by 14 ft wide (252 sq ft net) using a standard 12-foot wide carpet roll and a 10% seaming waste allowance:
- 1. Base Net Floor Area: 18 ft × 14 ft = 252 square feet.
- 2. Plan Roll Cuts (12 ft wide roll): Cut 1 is 12 ft × 18 ft = 216 sq ft (leaves a 2 ft × 18 ft strip along one side).
- 3. Cut 2 (Fill Piece): Requires ordering another 6 ft length off the 12 ft roll (yielding two 2x18 fill pieces running same nap direction).
- 4. Total Roll Linear Feet Needed: 18 ft + 6 ft = 24 linear feet of 12-ft broadloom.
- 5. Total Carpet Area Ordered: 24 linear ft × 12 ft wide = 288 square feet.
- 6. Convert to Square Yards: 288 sq ft ÷ 9 sq ft/yd = 32.0 Square Yards.
- 7. Underlayment Padding (8-lb 7/16"): 252 sq ft ÷ 9 = 28.0 Square Yards.
- 8. Estimated Material Cost (@ $28/sq yd): 32.0 sq yds × $28 = $896 for carpet + padding.
Popular Carpet Fiber Types & Underlayment Recommendations
| Carpet Fiber / Style | Durability Rating | Stain Resistance | Recommended Pad Density | Best Living Area |
|---|---|---|---|---|
| Nylon (Solution Dyed) | Highest (10/10) | Excellent (with Scotchgard) | 8 lb Rebond (7/16") | High-traffic stairs, hallways, family rooms |
| Triexta (SmartStrand) | High (9/10) | Permanent built-in stain lock | 8 lb Rebond / Memory foam | Homes with pets and young children |
| Polyester (PET) | Moderate (7/10) | Naturally stain resistant | 6–8 lb Rebond | Bedrooms, low-traffic guest suites |
| Wool (Natural Fiber) | High resilience | Moderate (requires care) | High-density felt pad | Formal living rooms, luxury estates |
| Berber / Loop Pile | Very high | Good (snag sensitive) | High-density 8-lb (max 3/8") | Home offices, basements, playrooms |
Frequently Asked Questions About Carpet Calculator
Why is carpet measured in square yards instead of square feet?
Historically and commercially, broadloom weaving mills manufacture carpet in square yards (where 1 square yard equals 9 square feet). To convert your room square footage into square yards, simply divide by 9.
What is "pile direction" and why does it ruin carpet seams if ignored?
Carpet fibers slant slightly in one direction coming off the manufacturing tufting loom. If two adjoining pieces are seamed with the nap slanting in opposing directions, light bounces off them differently, making one piece appear dark and the other light, even though they came from the same roll.
How thick should carpet padding be under residential carpet?
For plush residential cut-pile carpet, the Carpet and Rug Institute (CRI) recommends a padding thickness between 3/8" and 7/16" with a minimum density of 6 to 8 pounds per cubic foot. Never exceed 7/16" thickness, as overly squishy padding causes carpet backing to wrinkle and stretch.
Can you install new carpet over existing carpet padding?
Never install new carpet over old padding. Old pad breaks down, harbors decades of trapped pet dander and dust mite allergens, and loses elasticity in high-traffic walking paths, causing premature wear on expensive new carpet.
How much extra carpet should I order for waste?
A standard rectangular room requires about 10% waste to account for edge trimming and squaring. Rooms with multiple alcoves, diagonal walls, or stairs require 15% to 20% waste to maintain uniform pile nap alignment.