Concrete stairs calculator
Suits entrance or garden steps cast on soil or fill, and also shows the total rise and run of the flight.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter number of steps, stair width, riser height, tread depth and waste allowance.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Volume = width × tread × riser × n × (n + 1) ÷ 2, where n is the number of steps, since step k stands k risers above the ground. Then × (1 + waste ÷ 100).
Example
Inputs: Number of steps = 5, Stair width = 1.2 m, Riser height = 17 cm, Tread depth = 28 cm, Waste allowance = 5 %. Result: Concrete to order (with waste): 0.9 m³; Net volume: 0.8568 m³; Total rise: 85 cm.
Limits and caveats
- Assumes solid steps down to the ground, not a suspended stair on a sloping waist slab.
- A top landing is not included; add it with the general concrete calculator.
Questions about this tool
How much concrete for 5 steps 1.2 m wide?
With 17 cm risers and 28 cm treads the net volume is 0.857 m³, about 0.9 m³ with 5% waste.
What step sizes are comfortable?
Risers of 15 to 18 cm and treads of 28 to 30 cm are common, and many codes aim for 2 risers + tread of about 60 to 65 cm.
Can I use less concrete?
Yes, by filling the core with compacted soil or blocks and casting a shell over it, but this calculator assumes a solid pour.