Carpet Calculator
Use this carpet calculator to estimate both area and material cost for carpets, rugs, and other floor coverings. It follows the Omni setup for rectangular, circular, elliptical, pentagonal, hexagonal, and custom-shaped areas. That makes it useful whether you are pricing a full room, a stair landing, or a custom accent rug.
Carpet Estimate
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Quick Answer: Carpet cost is usually area multiplied by price per unit area. The key step is choosing the correct area formula for the shape: rectangle for standard rooms, circle or ellipse for round rugs, regular-polygon formulas for pentagons and hexagons, or a direct area entry for irregular layouts.
How to Calculate
- Choose the shape: Pick the shape that best matches the rug or floor section you want to cover.
- Enter the dimensions: Use the dimensions required for that shape, such as width and length or radius and price.
- Add the unit price: Use your quoted carpet or rug price per square foot, square meter, or other area unit.
- Review the total: The calculator returns the area and the corresponding estimated cost.
Formula
cost = area x price per unit area
| Variable | Meaning | Unit |
|---|---|---|
| area | Calculated carpet or rug area for the selected shape | sq units |
| price per unit area | Unit price for the material | currency per sq unit |
| shape dimensions | The side lengths, radii, or axes required for the chosen shape | length |
Worked Examples
Interior finishes - Rectangular room carpet
- Width: 12 ft
- Length: 15 ft
- Price: $4.50 / sq ft
Result: Area = 180 sq ft; cost = $810 before waste and installation
A rectangle is the simplest case and is often a good baseline before you add waste, seams, or underlay.
Interpretation Table
| Range | Meaning | Action |
|---|---|---|
| Lower area | Small rug or compact room | You may still want to add a waste allowance if pattern matching matters. |
| Higher area | Large room or large custom rug | Check roll width, seam layout, and delivery or installation costs. |
| Irregular shape | A layout that does not fit a basic formula | Use the custom-area option or split the floor into simpler shapes first. |
Frequently Asked Questions
First calculate the area of the floor or rug shape, then multiply that area by the price per unit area. You can then add waste, underlay, and installation separately.
Use the shape that best matches the space, or split the room into simpler sections and add their areas together. The custom-area option also works when you already know the floor area.
Usually yes. Pattern matching, room shape, seams, and trimming can increase the amount of material you should order beyond the exact mathematical area.
Note: This calculator estimates material area and cost only. Actual purchase quantity may be higher because of roll width, seams, trimming, and installation waste.
References
Last reviewed: March 14, 2026