{
    "name": "Door Frame Material Calculator",
    "url": "https://calculators.geekmidst.com/calculators/door-frame-material-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/door-frame-material-calculator.md",
    "category": "Construction",
    "description": "Work out the jamb and head cutting lengths for door frames, the total timber length, and how many stock lengths to buy when the cuts are nested.",
    "summary": "A door frame or lining is two jambs and a head. Enter the opening size and your stock length; the calculator lists the cuts and packs them into as few stock lengths as it can.",
    "also_called": [
        "Door lining calculator",
        "Door jamb 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": "width",
            "label": "Opening width between jambs",
            "type": "number",
            "default": "900",
            "unit": "mm"
        },
        {
            "name": "height",
            "label": "Opening height",
            "type": "number",
            "default": "2100",
            "unit": "mm"
        },
        {
            "name": "jamb_thickness",
            "label": "Head housing into each jamb",
            "type": "number",
            "default": "32",
            "unit": "mm"
        },
        {
            "name": "allowance",
            "label": "Extra length per jamb",
            "type": "number",
            "default": "50",
            "unit": "mm"
        },
        {
            "name": "doors",
            "label": "Number of frames",
            "type": "number",
            "default": "3"
        },
        {
            "name": "stock_length",
            "label": "Stock length",
            "type": "number",
            "default": "5400",
            "unit": "mm"
        },
        {
            "name": "waste",
            "label": "Waste allowance on length",
            "type": "number",
            "default": "10",
            "unit": "%"
        }
    ],
    "outputs": [
        {
            "key": "pieces",
            "label": "Stock lengths to buy",
            "format": "integer"
        },
        {
            "key": "jamb_cut",
            "label": "Jamb cut length",
            "format": "number"
        },
        {
            "key": "head_cut",
            "label": "Head cut length",
            "format": "number"
        },
        {
            "key": "net_length_m",
            "label": "Net length",
            "format": "number"
        },
        {
            "key": "order_length_m",
            "label": "Length with waste allowance",
            "format": "number"
        }
    ],
    "formula": {
        "text": "Jamb = H + allowance;  Head = W + 2 × housing;  Net = Frames × (2 × Jamb + Head);  Stock lengths by first-fit decreasing nesting of all cuts",
        "variables": {
            "W, H": "opening width and height",
            "housing": "head extension into each jamb"
        }
    },
    "worked_example": {
        "inputs": {
            "width": "900",
            "height": "2100",
            "jamb_thickness": "32",
            "allowance": "50",
            "doors": "3",
            "stock_length": "5400",
            "waste": "10"
        },
        "steps": [
            "Jamb = 2,100 + 50 = 2,150 mm; head = 900 + 2 × 32 = 964 mm.",
            "Net = 3 × (2 × 2,150 + 964) = 15,792 mm.",
            "Each 5.4 m length takes two jambs and a head (5,264 mm), so 3 lengths."
        ],
        "result": "Three 900 × 2,100 mm frames need 3 stock lengths of 5.4 m, about 15.8 m of timber."
    },
    "interpretation": "Buy the stock-length count; the waste-allowance length is a check for when you buy by the metre. Add a spare length if the timber quality is variable.",
    "assumptions": [
        "Saw kerf is ignored.",
        "Each frame is two jambs and one head of the same section."
    ],
    "limitations": [
        "Stops, architraves and thresholds are not included."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why is the head longer than the opening?",
            "answer": "When the head is housed into or runs over the jambs, each end gains the housing depth."
        },
        {
            "question": "Why not just divide total length by the stock length?",
            "answer": "Cuts cannot be joined, so off-cuts shorter than the next piece are wasted. Nesting the actual cuts gives the true count."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Window Frame Length Calculator",
            "url": "https://calculators.geekmidst.com/calculators/window-frame-length-calculator"
        },
        {
            "name": "Wall Stud Quantity Calculator",
            "url": "https://calculators.geekmidst.com/calculators/wall-stud-quantity-calculator"
        },
        {
            "name": "Material Waste Rate Calculator",
            "url": "https://calculators.geekmidst.com/calculators/material-waste-rate-calculator"
        }
    ],
    "disclaimer": "Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials.",
    "publisher": "GM¹X CalcVerse"
}