Calculate the volume of concrete and number of bags needed to pour a flight of concrete steps from the rise, run and width.
A flight of solid concrete steps forms a staircase shape. Each step sits on the full block below it, so the cross-section grows with every step. The calculator uses the run, rise and the number of steps to work out the cross-sectional area, then multiplies by the width.
For typical outdoor steps a rise of 150–180mm and a run of 280–300mm is comfortable. Add 5–10% waste for spillage and over-dig, and remember formwork and a compacted sub-base underneath.
It depends on the number of steps and their size. The calculator treats the flight as a solid staircase shape and works out the volume, bags and weight for you.
Around 150 to 180mm rise and 280 to 300mm run (going) is comfortable for outdoor steps. Keep every step the same size for safety.
Yes. Steps should sit on compacted hardcore and often a footing at the base to prevent settlement and cracking.
The calculator divides the total volume by the yield of a 25kg bag (about 0.0166 m³) and rounds up, but ready-mix is usually better for larger flights.
Yes, a 5 to 10 percent allowance covers spillage, over-dig and slightly oversized formwork so you do not run short mid-pour.
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