Calculating the amount of carpet needed for stairs involves measuring each step and multiplying by the number of steps, then adding extra for waste and overhang. Here's a step-by-step guide:
1. Measure Tread and Riser
- Tread: The tread is the horizontal part of the stair you step on. Measure its depth from the front edge to where it meets the riser.
- Riser: The riser is the vertical part of the stair. Measure its height from the top of one tread to the top of the next.
2. Calculate the Length Per Step
Add the tread measurement to the riser measurement. This gives you the length of carpet needed for each step.
- Example: If the tread is 10 inches and the riser is 7 inches, then each step requires 17 inches of carpet (10 + 7 = 17).
3. Count the Number of Steps
Accurately count the number of steps you need to cover with carpet. This includes the top landing if you intend to carpet it as well.
4. Calculate the Total Length
Multiply the length per step (calculated in step 2) by the total number of steps. This gives you the total length of carpet required.
- Example: If you have 12 steps and each step requires 17 inches of carpet, then you need 204 inches of carpet (17 x 12 = 204). This equates to 17 feet (204/12 = 17).
5. Measure the Width
Measure the width of your staircase. This will determine the width of the carpet you need to purchase. Make sure to measure at the widest point.
6. Add Extra for Waste
It's crucial to add extra carpet to account for waste, pattern matching (if applicable), and potential errors during installation. A general rule of thumb is to add 10-15% to your total length. For complex staircases or patterned carpets, adding even more is recommended.
7. Account for Overhang (Optional)
If you want the carpet to overhang the edge of the tread, add that amount to the tread measurement in step 1.
Example Calculation Summary:
| Step | Measurement/Action | Example |
|---|---|---|
| 1. Tread | Measure the depth of the tread. | 10 inches |
| 2. Riser | Measure the height of the riser. | 7 inches |
| 3. Length/Step | Tread + Riser | 17 inches (10 + 7) |
| 4. Number of Steps | Count the total steps. | 12 |
| 5. Total Length | Length/Step x Number of Steps | 204 inches (17 x 12 = 204) |
| = 17 feet | ||
| 6. Width | Measure the width of the stairs. | 3 feet |
| 7. Waste (10%) | Add 10% to the total length (Optional Pattern Match) | 1.7 feet (10% of 17ft) |
| 8. Total Carpet | Total Length + Waste | 18.7 feet (17 + 1.7) |
Therefore, you'd need approximately 18.7 feet of carpet that is 3 feet wide to carpet your stairs.
