How to Measure Stairs for Carpet: A Professional Guide with Photos
Why Accurate Stair Measurements Matter
Measuring stairs for carpet installation requires precision and attention to detail. Incorrect measurements can lead to wasted materials, poor fit, and additional costs. At Arra Flooring, we've helped countless customers achieve perfect stair carpeting with proper measurement techniques.
Whether you're planning a DIY project or preparing for professional installation, understanding how to measure stairs correctly is essential for a successful carpet fitting.
Tools You'll Need
Before you begin measuring your stairs for carpet, gather these essential tools:
- Steel measuring tape (at least 25 feet long)
- Notepad and pen for recording measurements
- Calculator for computing the total carpet needed
- Helper (recommended for safety and accuracy)
- A flashlight for measuring in poorly lit areas

Step-by-Step Measurement Guide
1. Measure Each Tread (Horizontal Surface)
The tread is the flat part of each step where you place your foot. Start from the bottom step and work your way up:
- Measure the width from wall to wall (or baluster to baluster)
- Measure the depth from front edge to back edge (typically 10-11 inches)
- Record measurements for each step - don't assume they're all identical
- Include any bullnose or rounded edges in your measurements

2. Measure Each Riser (Vertical Surface)
The riser is the vertical face of each step. Measure the height of each riser:
- Measure from the top of one step to the top of the next step
- Standard risers are usually 7-8 inches high
- Don't assume all risers are identical - older homes often have variations
- Measure at multiple points across the width to check for irregularities
3. Account for Stair Nosing
The nosing is the rounded or squared edge that overhangs the riser:
- Measure the overhang depth (usually 1-1.5 inches)
- This affects how much carpet wraps around each step
- Note the nosing style - rounded, squared, or bullnose
- Consider if you'll need special nosing strips for the installation
4. Measure Landings and Turns
Don't forget these critical areas:
- Top landing: Measure length and width
- Bottom landing: Include any transition areas
- Intermediate landings: For multi-level staircases
- Curved sections: Measure along the walking line
- Winder steps: Measure at the widest and narrowest points
Calculating Total Carpet Needed

The Waterfall Method
This is the most common and cost-effective installation method:
- Add up all tread depths (front-to-back measurements)
- Add up all riser heights (vertical measurements)
- Add measurements for all landings
- Add a 10-15% waste factor for cuts and mistakes
- Consider carpet width - most residential carpet is 12 feet wide
Sample Calculation
Example: 13-step staircase (36 inches wide)
- Treads: 13 steps × 11 inches = 143 inches
- Risers: 13 steps × 7.5 inches = 97.5 inches
- Top landing: 36" × 36" = 36 inches
- Total length needed: 276.5 inches (23 feet)
- Width needed: 36 inches
- With 10% waste: 25.3 linear feet
- Final order: 26 linear feet of 36" wide carpet
Professional Tips from Arra Flooring
🎯 Double-check everything
Measure twice, order once. Small errors can lead to big problems.
🧭 Consider carpet direction
Plan the direction the pile will face to achieve a consistent appearance.
🎨 Account for pattern matching
Patterned carpets need extra material for proper alignment.
🏠 Check for irregularities
Older homes may have non-standard measurements throughout.
Standard Measurement Mistakes to Avoid
- ❌ Assuming all steps are identical - Always measure each step individually
- ❌ Forgetting to measure landings - These add significant square footage
- ❌ Not accounting for carpet thickness - Thick carpet affects fit
- ❌ Insufficient waste allowance - Always add 10-15% extra
- ❌ Measuring in different units - Stick to inches or centimeters consistently
- ❌ Ignoring carpet pile direction - This affects appearance and wear
- ❌ Not considering installation method - Different methods need different amounts
When to Call the Professionals
While measuring stairs is achievable for DIYers, consider professional help for:
- Curved or spiral staircases - Complex geometry requires expertise
- Multiple turns and landings - Intricate layouts need professional assessment
- Valuable carpet materials - Expensive materials warrant professional handling
- Structural irregularities - Older homes with non-standard construction
- Time constraints - Professional measurement saves time and ensures accuracy
- Insurance considerations - Professional installation often includes warranties

Ready for Professional Installation?
Get Expert Carpet Installation
At Arra Flooring, our experienced team provides accurate measurements and professional installation for all types of staircases. We serve customers throughout Ireland with premium carpet solutions and expert craftsmanship.
📞 Contact us today for a free consultation and quote
0894913520
Let our professionals ensure your stair carpet installation is perfect from the first step to the last.