Concrete Stairs Calculator

Your details

Total number of risers (steps) in the staircase.
Horizontal depth of each step. US building codes require at least 10 in (25 cm).
in
Vertical height of each step. US codes limit this to 7.75 in (19.7 cm) maximum.
in
Side-to-side width of the staircase. Minimum 36 in (91 cm) for residential.
in
Thickness of the concrete carriage measured perpendicular to the slope. Typically 6-8 in (15-20 cm).
in
Enable if the risers slope inward rather than being perfectly vertical (common in decorative pours).
Extra concrete to order above the calculated volume to cover spills, compaction loss, and uneven substrate. 10% is typical.
%
Pre-mixed concrete bag size used to calculate bag count.
Cost of one pre-mixed concrete bag at your local supplier. Leave at 0 to skip cost estimate.
USD
Concrete volume (net)
0.459m³

Net volume of concrete required, before wastage.

Volume to order (incl. wastage)0.505m³
Volume to order0.661yd³
Estimated weight1,212kg
Bags needed30
Estimated material cost225USD
Total rise (staircase height)35in
Total run (staircase length)55in
Stair angle32.5°
Net volume (m3)0.459
Volume with wastage (m3)0.505

5 steps, 0.505 m3 of concrete needed (with wastage).

  • Rise + run = 18.0 in, which falls in the ideal 17-18 in ergonomic range for comfortable climbing.
  • You need 30 bags including wastage - a typical DIY load that can be mixed on site.
  • The 32.5° stair angle is within the typical comfortable range of 20-50°.

Next stepMix bags in small batches to keep concrete workable. Budget around 30-45 minutes of working time per batch in moderate temperatures.

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