{
    "name": "Thermal Expansion Calculator",
    "url": "https://calculators.geekmidst.com/calculators/thermal-expansion-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/thermal-expansion-calculator.md",
    "category": "Science & engineering",
    "description": "Calculate how much a rod, pipe, rail or volume of liquid grows or shrinks with temperature, from its expansion coefficient and temperature change.",
    "summary": "Most materials grow in proportion to their size and the temperature rise: ΔL = αL₀ΔT for length, ΔV = βV₀ΔT for volume.",
    "also_called": [
        "Linear expansion calculator",
        "Volume expansion 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": "mode",
            "label": "Expansion type",
            "type": "segmented",
            "default": "linear",
            "options": {
                "linear": "Linear (length)",
                "volume": "Volumetric"
            }
        },
        {
            "name": "size",
            "label": "Original size",
            "type": "number",
            "default": "10000"
        },
        {
            "name": "coefficient",
            "label": "Expansion coefficient",
            "type": "number",
            "default": "12",
            "unit": "× 10⁻⁶ /K"
        },
        {
            "name": "t_initial",
            "label": "Initial temperature",
            "type": "number",
            "default": "20",
            "unit": "°C"
        },
        {
            "name": "t_final",
            "label": "Final temperature",
            "type": "number",
            "default": "50",
            "unit": "°C"
        }
    ],
    "outputs": [
        {
            "key": "change",
            "label": "Change in size",
            "format": "number"
        },
        {
            "key": "final_size",
            "label": "Final size",
            "format": "number"
        },
        {
            "key": "percent_change",
            "label": "Relative change",
            "format": "percent"
        },
        {
            "key": "strain_ppm",
            "label": "Thermal strain",
            "format": "number"
        }
    ],
    "formula": {
        "text": "ΔL = α × L₀ × ΔT;  ΔV = β × V₀ × ΔT;  final size = original + change",
        "variables": {
            "α, β": "linear or volumetric expansion coefficient, per kelvin",
            "L₀, V₀": "original length or volume",
            "ΔT": "final minus initial temperature"
        }
    },
    "worked_example": {
        "inputs": {
            "mode": "linear",
            "size": "10000",
            "coefficient": "12",
            "t_initial": "20",
            "t_final": "50"
        },
        "steps": [
            "ΔT = 50 − 20 = 30 K.",
            "ΔL = 12 × 10⁻⁶ × 10 000 mm × 30 = 3.6 mm.",
            "Final length = 10 000 + 3.6 = 10 003.6 mm (0.036% longer)."
        ],
        "result": "A 10 m steel member warmed by 30 K grows by 3.6 mm."
    },
    "interpretation": "Restrained members cannot grow freely, so the same strain turns into stress. That is why pipes have expansion loops and bridges have expansion joints.",
    "assumptions": [
        "The coefficient is constant over the temperature range.",
        "The object can expand freely."
    ],
    "limitations": [
        "Water is anomalous below 4 °C and its β changes strongly with temperature; use β at the mean temperature.",
        "Not valid across phase changes."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "How are α and β related?",
            "answer": "For an isotropic solid, β ≈ 3α. Liquids have only a volumetric coefficient."
        },
        {
            "question": "What does “× 10⁻⁶ /K” mean?",
            "answer": "Micrometres of growth per metre of length per kelvin. Steel at 12 grows 12 µm per metre for each degree."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Heat Capacity Calculator",
            "url": "https://calculators.geekmidst.com/calculators/heat-capacity-calculator"
        },
        {
            "name": "Length Converter",
            "url": "https://calculators.geekmidst.com/calculators/length-converter"
        },
        {
            "name": "Temperature Converter",
            "url": "https://calculators.geekmidst.com/calculators/temperature-converter"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}