How to Measure Your Stairs Correctly
Calculating carpet for stairs requires more than a simple area measurement. You must measure the two key parts of each step and combine them:
Tread: The flat, horizontal part you step on. Measure from the back to the very front edge (including the "nosing" or lip).
Riser: The vertical face of the step. Measure from the top of one tread to the bottom of the next tread above it.
Why Waste Factor is Crucial for Stairs
| Reason | Explanation |
|---|---|
| Pattern Matching | If your carpet has a pattern, you will need extra material to ensure the pattern aligns correctly from one step to the next. |
| Directional Grain | Most carpets have a "grain" or "pile direction." All pieces must be laid in the same direction to avoid a mismatched look, which often results in more waste. |
| Cuts & Mistakes | Stairs involve complex cuts. A 15-20% waste factor provides a necessary buffer for cutting errors or mis-measurements. |
How to Use the Calculator
- Count the total number of stairs you wish to carpet.
- Measure the depth of a single tread and the height of a single riser in inches.
- Measure the width of the stairs in feet.
- Enter your carpet's price per square yard.
- Select a waste factor. 15% is a safe minimum for stairs. Use 20% for patterned carpets.
- Click "Calculate Carpet" for your material estimate.
Frequently Asked Questions
What about landings?
This calculator is for stairs only. For landings (flat platform areas), you should use the standard Flooring Calculator, calculate the area, and add it to the total from this calculator.
What if my stairs are curved or triangular (winders)?
For winder stairs, measure the tread depth at its absolute widest point and use that value for the calculation. This will overestimate the material needed, which is much safer than underestimating. Always buy extra for complex stairs.