Concrete Stairs Calculator
Calculate concrete volume needed for stairs with steps, carriage, and building code validation
1Stair Dimensions
Horizontal depth of each step
Vertical height between steps
Thickness of the stair carriage/slab
Width of the staircase
2Concrete Properties
Recommended: 5-10% for spillage
3Volume Results
Enter all stair dimensions to see volume calculations
Required: steps, tread run, riser rise, throat depth, and width
How to Use the Concrete Stairs Calculator
Step-by-Step Instructions
- 1Select your measurement units (feet, inches, meters, or centimeters)
- 2Enter the number of steps in your staircase
- 3Input tread run (going), riser rise, and throat depth
- 4Specify the stair width and check angled risers if applicable
- 5Set waste percentage and concrete properties
- 6Review building code warnings and adjust dimensions if needed
Calculation Formulas
Step Area = (T × R) ÷ 2
Carriage Area = √(T² + R²) × D
Volume = (Step + Carriage) × N × W
Where:
- • T = Tread run, R = Riser rise
- • D = Throat depth, N = Number of steps
- • W = Stair width
Building Code Guidelines
- Riser height: 4" to 7.75" (typical residential)
- Tread run: minimum 11" depth
- 2R + T rule: should equal 24-25"
- Minimum width: 36" (residential)
Stair Design Components
Step Components
- Tread: Horizontal surface you step on
- Riser: Vertical face between steps
- Nosing: Overhang at front of tread
- Going: Horizontal distance between risers
Carriage Structure
- Throat Depth: Carriage thickness
- String: Supporting beam structure
- Soffit: Underside of stair structure
- Waist: Thinnest part of carriage
Safety Features
- Handrails: Required for safety
- Landings: Required every 12' rise
- Lighting: Adequate illumination
- Non-slip: Textured surface finish
Example Calculation
Sample Staircase
Calculation Results
⚠️ Safety and Building Code Requirements
Critical Safety Requirements
- Always follow local building codes and permit requirements
- Ensure proper structural support and foundation design
- Install handrails at required heights (34"-38")
- Provide adequate lighting and non-slip surfaces
Construction Best Practices
- Use proper reinforcement for structural stairs
- Ensure consistent riser heights and tread depths
- Plan for proper drainage and waterproofing
- Allow adequate curing time before use (28 days)
Professional Consultation Required: Concrete stairs are structural elements that must comply with building codes and safety regulations. Always consult with a licensed structural engineer and obtain proper permits. This calculator provides estimates for planning purposes and should not replace professional engineering analysis and code compliance verification.