{
  "@context": "https://schema.org",
  "@type": "Dataset",
  "name": "How do you calculate concrete for stairs?",
  "description": "Treat the staircase as a series of rectangles: compute each step's volume (width × tread depth × cumulative height) and add them, then divide by 27. Three 4-ft-wide steps with 7-inch rises and 11-inch treads total about 0.30 yards — roughly 14 bags of 80-lb mix.",
  "url": "https://www.revenuelab.fyi/answers/how-to-calculate-concrete-for-stairs",
  "dateModified": "2026-10-01",
  "creator": {
    "@type": "Organization",
    "name": "RevenueLab",
    "url": "https://www.revenuelab.fyi"
  },
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "keywords": [
    "Concrete Cost Calculator",
    "Concrete Slab Cost Calculator",
    "Concrete Slab Material Calculator"
  ],
  "distribution": {
    "@type": "DataDownload",
    "contentUrl": "https://www.revenuelab.fyi/api/public/page.json?path=answers%2Fhow-to-calculate-concrete-for-stairs",
    "encodingFormat": "application/json"
  },
  "json": {
    "type": "answer",
    "question": "How do you calculate concrete for stairs?",
    "shortAnswer": "Treat the staircase as a series of rectangles: compute each step's volume (width × tread depth × cumulative height) and add them, then divide by 27. Three 4-ft-wide steps with 7-inch rises and 11-inch treads total about 0.30 yards — roughly 14 bags of 80-lb mix.",
    "tableTitle": "Worked example: 3-step stoop, 4 ft wide, 7 in rise, 11 in tread",
    "columns": [
      "Step",
      "Height at that step",
      "Volume"
    ],
    "rows": [
      {
        "label": "Step 1 (bottom)",
        "value": "7 in",
        "note": "4 × 0.917 × 0.583 = 2.14 ft³"
      },
      {
        "label": "Step 2",
        "value": "14 in",
        "note": "4 × 0.917 × 1.167 = 4.28 ft³"
      },
      {
        "label": "Step 3 (top)",
        "value": "21 in",
        "note": "4 × 0.917 × 1.75 = 6.42 ft³"
      },
      {
        "label": "Total",
        "value": "12.83 ft³",
        "note": "÷ 27 = 0.48 yd³ solid-cast"
      }
    ],
    "context": "Most residential stoops are poured solid (as computed above) because the forms are simpler than building a hollow structure; large commercial stairs use a sloped slab with formed risers, which uses roughly half the concrete. Code sets the geometry: 7–7¾ inch maximum rise, 11-inch minimum tread, and consistent dimensions across the flight — a ¼-inch variation between steps is a trip hazard and an inspection failure.",
    "methodology": "Solid-cast volume computed as the sum of step rectangles. Dimensions follow IRC R311.7 (max 7¾-in rise, min 10-in tread with nosing, ≤3/8-in variation). The hollow alternative is shown for comparison only.",
    "dateModified": "2026-10-01",
    "relatedCalculators": [
      {
        "label": "Concrete Cost Calculator",
        "to": "/concrete-cost-calculator"
      },
      {
        "label": "Concrete Slab Cost Calculator",
        "to": "/concrete-slab-cost-calculator"
      },
      {
        "label": "Concrete Slab Material Calculator",
        "to": "/concrete-slab-material-calculator"
      }
    ],
    "relatedReading": [
      {
        "label": "Concrete for a slab",
        "to": "/answers/how-to-calculate-concrete-for-a-slab"
      }
    ]
  }
}