Concrete Stair Calculator
This concrete stair calculator computes solid poured steps: each step is a stacked block, so volume grows with the square of the step count. Enter steps, rise, run and width — plus an optional top landing.
Como usar esta calculadora
- Insira suas dimensões — pés para comprimentos, polegadas para a espessura.
- Ajuste as opções — porcentagem de desperdício, tamanho do saco e o preço local do concreto.
- Leia seus resultados — volume, sacos, peso e custo são atualizados ao vivo enquanto você digita.
A fórmula
Stairs volume = width × run × rise × n(n+1)/2 for n steps (solid fill on grade) Exemplo resolvido: 4 steps at 7 in rise, 11 in run, 4 ft wide: 4 × 0.917 × 0.583 × (4×5/2) = 21.4 ft³ ≈ 0.79 yd³ — about 36 × 80 lb bags.
A concrete calculator for stairs can't just multiply three numbers — solid steps stack, so the first step's column of concrete is one riser tall, the second two risers, and so on. That triangular-number formula (n(n+1)/2) is built in.
Standard step geometry: 7–7.5 inch rise, 11 inch run, and a width of at least 36 inches (48 inches is comfortable). Building codes require riser heights to be consistent within 3/8 inch.
Adding a top landing? Enter its depth and the calculator adds a platform slab at full stair height. For steps against a wall or over a void, formed (hollow) stairs use much less concrete — this tool assumes solid fill on grade, the common DIY case.
Perguntas frequentes
Perguntas comuns sobre a concrete stair calculator.
How much concrete for 4 steps?
At standard 7 in rise / 11 in run and 4 ft width, about 0.79 yd³ (21.4 ft³) solid-filled — roughly 36 × 80 lb bags. Add 10% waste for stepped forms.
What rise and run should concrete steps have?
7 to 7.5 inches of rise and 11 inches of run is the comfortable, code-friendly standard. Keep all risers equal.
Why does step count increase volume so fast?
Because solid stairs stack: n steps contain n(n+1)/2 step-blocks of concrete. Doubling steps roughly quadruples volume.
Can I reduce the concrete needed for stairs?
Yes — fill the core with compacted rubble or form the underside. This calculator's solid-fill number is your maximum.
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