How much carpet for stairs?
For straight stairs, measure stair width plus tread and riser dimensions. The calculator converts the stair surface area into square yards and adds waste.
Roll layout matters
Carpet roll width, seam direction, pattern repeat, stairs, closets, and room shape can make the final order larger than a pure area conversion.
Square feet vs square yards
One square yard is 9 square feet. A 250 sq ft room is 27.78 sq yards before waste.
Stair carpet example estimates
Examples are for straight stairs before landings, turns, roll layout, and pattern matching.
| Stair example | Dimensions | Sq yards with 15% waste |
|---|---|---|
| 10 straight stairs | 3 ft wide, 10 in tread, 7 in riser | 5.43 sq yd |
| 12 straight stairs | 3 ft wide, 10 in tread, 7 in riser | 6.52 sq yd |
| 14 straight stairs | 3.5 ft wide, 10 in tread, 7 in riser | 8.87 sq yd |
Carpet square feet to square yards
Square yards = square feet / 9 before waste. Roll layout and seams can increase final ordering.
| Floor area | Sq yards before waste | Sq yards with 10% waste |
|---|---|---|
| 100 sq ft | 11.11 sq yd | 12.22 sq yd |
| 250 sq ft | 27.78 sq yd | 30.56 sq yd |
| 500 sq ft | 55.56 sq yd | 61.11 sq yd |
| 1000 sq ft | 111.11 sq yd | 122.22 sq yd |
Before you calculate
- Measure each room separately and include closets or alcoves that need carpet.
- Keep roll width, seam direction, and pattern repeat in mind when using area-based estimates.
- Use carpet tile coverage when estimating modular carpet rather than broadloom rolls.
Common mistakes
- Converting square feet to square yards without considering roll layout.
- Ignoring seams, pattern matching, stairs, or closets.
- Using net room area as the final order quantity.
Formula
sq yards = stairs * stairWidth * ((treadDepth + riserHeight) / 12) / 9 * (1 + wastePercent / 100)
Assumptions
- This estimates runner material for straight stairs.
- Landings, turns, binding, rods, and pattern matching are not included.
- Installer layout can change final ordering.
Example
Estimated stair carpet needed: 5.43 sq yards
How to use this calculator
- Enter stairs in count.
- Enter stair width in ft.
- Enter tread depth in in.
- Enter riser height in in.
- Enter waste in %.
- Review the live estimate and compare it with the example result.
- Check the formula, assumptions, product labels, and site conditions before using the Carpet Runner Calculator result to plan materials.
Before you buy materials
- Confirm roll width, minimum order quantity, and installer layout before buying.
- Keep a small amount of extra material for repairs when practical.
FAQ
What is the example carpet runner square-yard result?
Use stairs, stair width, tread depth, riser height, then calculate the planning result. In the default example, the result is 5.43 sq yards.
How do I convert carpet square feet to square yards?
Divide square feet by 9. Then add waste for seams, roll layout, closets, and pattern matching.
Does this include carpet padding?
No. Carpet and padding may be estimated separately because product coverage, seams, and installation details can differ.
Should stairs be calculated separately?
Yes. Stairs use tread, riser, width, landings, and pattern direction, so they should not be hidden inside a simple floor-area estimate.
Can I order carpet from square yards alone?
Use square yards as a planning estimate, then confirm roll width, seams, pattern repeat, and installer layout.
Related calculators
This calculator is for planning estimates only. Verify final quantities with product labels, project conditions, and a qualified professional when accuracy matters.