2.8 m rise in metric
Input Rise 2.8 m, riser 18 cm, tread 28 cm, width 1 m, waist 10 cm, waste 10%.
Result 16 risers at 17.5 cm, 15 treads, 4.20 m run, 5.05 m stringer and about 0.96 m³ of concrete.
Concrete Stair Calculator
Home & RenovationWork out risers, treads, total run, stringer length and the concrete volume for a straight staircase.
Your inputs
Result
Concrete volume
—
m³
- Risers —
- Actual riser height — cm
- Treads —
- Total run — m
- Stringer length — m
Change any input and the result updates instantly.
Formula and rules
- Risers = total rise ÷ target riser height, rounded up
- Actual riser height = total rise ÷ risers
- Treads = risers − 1; total run = treads × tread depth
- Stringer length = √(total rise² + total run²)
- Concrete volume = width × ½ × riser × tread × treads + width × stringer × waist thickness
- Order volume = concrete volume × (1 + waste %)
Worked examples
8 ft rise in imperial
Input Rise 8 ft, riser 7.5 in, tread 10 in, width 3 ft, waist 4 in, waste 10%.
Result 13 risers at 7.4 in, 12 treads, 10 ft run, 12.8 ft stringer and about 24 ft³ of concrete.
FAQ
What is a comfortable riser height?
Most building codes keep risers between 15 and 20 cm (6–8 in) with treads of 25–30 cm (10–12 in). A 17–18 cm riser with a 28 cm tread suits most adults.
Why does the riser count round up?
You cannot build a partial step, so the count is rounded up and the rise is then spread evenly. That makes the real riser height slightly lower than your target, which this tool recalculates.
Does the concrete volume include the waist slab?
Yes. The stepped triangular section and the sloped waist slab are both measured, then the waste allowance is added. Rebar, formwork and the compacted sub-base are not included.
Disclaimer: Results follow the formula shown on this page and are for reference only. Real-world quantities vary with materials, technique and conditions, so allow a margin before ordering.