Stair Carpet Calculator
Calculate carpet dimensions, area, and cost for stair installation projects
Calculate Stair Carpet Requirements
Count every floor rise as one step
Vertical distance between steps
Horizontal distance (riser to riser)
Distance between walls/stringers
Platform/landing length (optional)
Carpet Allowances
Safety margin for measurement errors
For tucking edges against walls
Carpet Requirements
Formula used: L = n × V + (n-1) × T + D + allowance
Steps length: 0.0cm
Cost Calculation (Optional)
Example Calculation
4-Step Staircase with Rounded Nosing
Steps: 4 steps
Riser Rise: 18.0 cm
Tread Run: 25.0 cm
Stair Width: 100.0 cm
Landing Depth: 100.0 cm
Nosing: Rounded, 2.5 cm overhang, 2.0 cm thick
Allowances: 10 cm length, 2 cm width
Results
Nosing Perimeter = 2×(2.5-1.0) + π×1.0 = 6.14 cm
Vertical per Step = 18.0 - 2.0 + 6.14 = 22.14 cm
Steps Length = 4×22.14 + 3×25.0 = 163.56 cm
Total Length = 163.56 + 100.0 + 10.0 = 273.56 cm
Total Width = 100.0 + 2.0 = 102.0 cm
Total Area: 2.79 m²
Installation Tips
Start Direction
Start from bottom for overhanging nosings
Easier to tuck and staple underneath
Tools Needed
Hammers, staplers, utility knives
Carpet knee kickers and power stretchers
Additional Materials
Tack strips and underlayment
Optional: Double-sided adhesive tapes
Nosing Shape Guide
Rounded (Bullnose)
Most common, smooth curved edge
Formula: 2×(o-t/2) + π×t/2
Rectangular
Square-edged overhang
Formula: 2×o + t
Triangular
Angled overhang design
Formula: o + √(o²+t²)
Understanding Stair Carpet Calculations
Key Measurements
Accurate carpet calculations prevent waste and ensure you order the right amount. The key is understanding how nosing shapes affect the total perimeter that needs covering.
Why Accuracy Matters
- •Prevents costly material waste or shortages
- •Ensures proper coverage of all step surfaces
- •Accounts for installation challenges and tucking
- •Provides allowances for measurement variations
Calculation Formulas
Vertical per Step: V = R - t + P
Rounded Nosing: P = 2×(o-t/2) + π×t/2
Rectangular Nosing: P = 2×o + t
Triangular Nosing: P = o + √(o²+t²)
Total Length: L = n×V + (n-1)×T + D + allowance
Total Width: W = stair_width + width_allowance
Area: A = L × W
Pro Tip: Always add 10-15% extra material for installation errors, pattern matching, and future repairs.
Installation Considerations
Stair Runner vs. Full Coverage
For stair runners, use the same length calculation but choose a narrower width, leaving hardwood exposed on both sides for aesthetic appeal.
Pattern Matching
If your carpet has patterns, you may need additional material to ensure proper pattern alignment across all steps.