{
    "name": "Wall Plastering Quantity Calculator",
    "url": "https://calculators.geekmidst.com/calculators/wall-plastering-quantity-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/wall-plastering-quantity-calculator.md",
    "category": "Construction",
    "description": "Estimate cement bags and sand for cement-sand plaster from the wall area, openings, plaster thickness, mix ratio and a dry-volume factor.",
    "summary": "Plaster volume is the net wall area times the thickness. Scale it up for uneven surfaces and dry bulk, then split it by the cement-to-sand ratio.",
    "also_called": [
        "Plastering material calculator",
        "Rendering calculator"
    ],
    "applies_to": "Worldwide",
    "last_updated": "2026-10-29",
    "computation": "Results are computed in the visitor’s browser on the HTML page. This API describes the calculator; it does not compute results.",
    "inputs": [
        {
            "name": "units",
            "label": "Units",
            "type": "segmented",
            "default": "metric",
            "options": {
                "metric": "Metric",
                "imperial": "Imperial"
            }
        },
        {
            "name": "length",
            "label": "Wall length",
            "type": "number",
            "default": "5"
        },
        {
            "name": "height",
            "label": "Wall height",
            "type": "number",
            "default": "3"
        },
        {
            "name": "openings",
            "label": "Doors and windows (total area)",
            "type": "number",
            "default": "3",
            "optional": true
        },
        {
            "name": "thickness",
            "label": "Plaster thickness",
            "type": "number",
            "default": "12"
        },
        {
            "name": "cement_parts",
            "label": "Cement parts",
            "type": "number",
            "default": "1"
        },
        {
            "name": "sand_parts",
            "label": "Sand parts",
            "type": "number",
            "default": "4"
        },
        {
            "name": "dry_factor",
            "label": "Dry-volume factor",
            "type": "number",
            "default": "1.27"
        },
        {
            "name": "cement_density",
            "label": "Cement bulk density",
            "type": "number",
            "default": "1440",
            "unit": "kg/m³"
        },
        {
            "name": "bag_kg",
            "label": "Cement bag size",
            "type": "number",
            "default": "50",
            "unit": "kg"
        },
        {
            "name": "waste",
            "label": "Waste allowance",
            "type": "number",
            "default": "10",
            "unit": "%",
            "optional": true
        }
    ],
    "outputs": [
        {
            "key": "bags",
            "label": "Cement bags (rounded up)",
            "format": "integer"
        },
        {
            "key": "cement_kg",
            "label": "Cement",
            "format": "number"
        },
        {
            "key": "sand_m3",
            "label": "Sand",
            "format": "number"
        },
        {
            "key": "sand_ft3",
            "label": "Sand",
            "format": "number"
        },
        {
            "key": "area_m2",
            "label": "Plastered area",
            "format": "number"
        },
        {
            "key": "area_ft2",
            "label": "Plastered area",
            "format": "number"
        },
        {
            "key": "wet_m3",
            "label": "Wet plaster volume",
            "format": "number"
        },
        {
            "key": "dry_m3",
            "label": "Dry material volume",
            "format": "number"
        }
    ],
    "formula": {
        "text": "Area = L × H − Openings;  Wet = Area × t;  Dry = Wet × (1 + Waste) × Dry factor;  Cement = Dry × c ÷ (c + s) × density;  Sand = Dry × s ÷ (c + s)",
        "variables": {
            "t": "plaster thickness",
            "c : s": "cement-to-sand ratio"
        }
    },
    "worked_example": {
        "inputs": {
            "units": "metric",
            "length": "5",
            "height": "3",
            "openings": "3",
            "thickness": "12",
            "cement_parts": "1",
            "sand_parts": "4",
            "dry_factor": "1.27",
            "cement_density": "1440",
            "bag_kg": "50",
            "waste": "10"
        },
        "steps": [
            "Area = 5 × 3 − 3 = 12 m²; wet volume = 12 × 0.012 = 0.144 m³.",
            "Dry volume = 0.144 × 1.10 × 1.27 = 0.2012 m³.",
            "Cement = 0.2012 × 1/5 × 1440 = 57.9 kg → 2 bags of 50 kg; sand = 0.2012 × 4/5 = 0.161 m³."
        ],
        "result": "Plastering 12 m² at 12 mm in 1:4 takes about 58 kg of cement (2 bags) and 0.16 m³ of sand."
    },
    "interpretation": "Plaster both faces of a wall by doubling the area. Rough brickwork or block takes more than smooth concrete, so raise the waste allowance for poor backgrounds.",
    "assumptions": [
        "Uniform thickness over the whole area.",
        "Cement-sand plaster; gypsum and lime plasters are batched differently."
    ],
    "limitations": [
        "Reveals, beads and ceiling work are not itemised."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why add a waste allowance as well as the dry factor?",
            "answer": "The dry factor converts wet to dry volume; the allowance covers material that fills hollows in the wall and drops to the floor."
        },
        {
            "question": "How thick should plaster be?",
            "answer": "Commonly 12 mm on internal brick walls and 15–20 mm in two coats outside, but follow your specification."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Sand Quantity for Mortar Calculator",
            "url": "https://calculators.geekmidst.com/calculators/sand-quantity-for-mortar-calculator"
        },
        {
            "name": "Brick Quantity Calculator",
            "url": "https://calculators.geekmidst.com/calculators/brick-quantity-calculator"
        },
        {
            "name": "Paint Coverage Calculator",
            "url": "https://calculators.geekmidst.com/calculators/paint-coverage-calculator"
        },
        {
            "name": "Waterproofing Area Calculator",
            "url": "https://calculators.geekmidst.com/calculators/waterproofing-area-calculator"
        }
    ],
    "disclaimer": "Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials.",
    "publisher": "GM¹X CalcVerse"
}