Concrete Steps Calculator

Calculate the exact amount of concrete needed for your staircase project, including steps, landings, and waste factor.

Imperial
Metric
Include top platform as one step Please enter a valid number (minimum 1)
Total width of staircase Please enter a valid width
7-8" recommended Please enter a valid height
10-11" recommended Please enter a valid depth
Thickness under steps (4-6" typical) Please enter a valid depth
Leave empty if no landing Please enter a valid depth
Advanced Options
Recommended: 10% for waste
For cost estimation

How to Use This Calculator

Follow these steps to calculate the concrete needed for your staircase:

  • Step 1: Enter the total number of steps, including the top platform if applicable
  • Step 2: Input the width of your staircase (typical residential: 36-48 inches)
  • Step 3: Enter the riser height (vertical part). Building codes typically require 7-8 inches maximum
  • Step 4: Enter the tread depth (horizontal part). Standard is 10-11 inches minimum
  • Step 5: Specify the throat depth (concrete thickness under the steps). Use 4-6 inches for residential
  • Step 6: Add platform depth if you have a landing at the top (optional)
  • Step 7: Check "angled risers" if your design includes nosing overhang
  • Step 8: Set wastage percentage (10% recommended for spills and uneven ground)
  • Step 9: Click Calculate to see your results

Pro Tip: Always order 10-15% more concrete than calculated to account for waste, spillage, and uneven subgrade.

Formula Used

The calculator uses the following formulas:

Step Volume:
Step Area = (Tread Depth × Riser Height) ÷ 2
Step Volume = Step Area × Stair Width
Total Steps Volume = Step Volume × Number of Steps
Carriage (Stringer) Volume:
Carriage Area = (Total Rise × Total Run) ÷ 2
Carriage Volume = Carriage Area × Throat Depth
Total Carriage Volume = Carriage Volume × Number of Stringers
Platform Volume (if applicable):
Platform Volume = Platform Depth × Stair Width × Riser Height
Total Concrete:
Total Volume = Steps Volume + Carriage Volume + Platform Volume
With Waste = Total Volume × (1 + Waste%)
Cubic Yards = Total Volume (cu ft) ÷ 27
Bag Calculations:
40 lb bags = Total Volume (cu ft) ÷ 0.30
60 lb bags = Total Volume (cu ft) ÷ 0.45
80 lb bags = Total Volume (cu ft) ÷ 0.60

Construction Tips

  • Formwork: Use 2× lumber for forms. Brace heavily—wet concrete exerts tremendous pressure
  • Reinforcement: Install rebar or wire mesh in the throat area to prevent cracking
  • Concrete Mix: Use 3500-4000 PSI mix for outdoor stairs. Add air entrainment in freeze-thaw climates
  • Slope: Maintain consistent riser heights (max 3/8" variation per code)
  • Finishing: Broom finish for traction. Slope treads 1/4" per foot for drainage
  • Curing: Keep moist for 7 days minimum. Use curing compound or wet burlap
  • Control Joints: Install at 4-5 foot intervals to control cracking
  • Weather: Avoid pouring below 40°F or above 90°F without special precautions
  • Building Codes: Check local requirements for riser max (usually 7.75"), tread min (usually 10"), and handrail needs