{
    "name": "Molecular Weight Calculator",
    "url": "https://calculators.geekmidst.com/calculators/molecular-weight-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/molecular-weight-calculator.md",
    "category": "Science & engineering",
    "description": "Type a chemical formula such as C6H12O6, Ca(OH)2 or CuSO4·5H2O to get its molar mass in g/mol and the mass percentage of each element.",
    "summary": "The molar mass of a compound is the sum of the standard atomic weights of its atoms. This calculator reads the formula, including brackets and hydrates, and adds them up using IUPAC/CIAAW values.",
    "also_called": [
        "Molar mass calculator",
        "Formula mass 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": "formula",
            "label": "Chemical formula",
            "type": "text",
            "default": "C6H12O6"
        }
    ],
    "outputs": [
        {
            "key": "molar_mass",
            "label": "Molar mass",
            "format": "number"
        },
        {
            "key": "atoms",
            "label": "Atoms per formula unit",
            "format": "integer"
        },
        {
            "key": "elements",
            "label": "Different elements",
            "format": "integer"
        }
    ],
    "formula": {
        "text": "M = Σ (number of atoms of each element × its standard atomic weight)",
        "variables": {
            "M": "molar mass in g/mol (numerically equal to the molecular weight in daltons)",
            "atomic weights": "CIAAW abridged standard atomic weights, e.g. H 1.0080, C 12.011, O 15.999"
        }
    },
    "worked_example": {
        "inputs": {
            "formula": "C6H12O6"
        },
        "steps": [
            "Carbon: 6 × 12.011 = 72.066.",
            "Hydrogen: 12 × 1.008 = 12.096.",
            "Oxygen: 6 × 15.999 = 95.994.",
            "Total = 72.066 + 12.096 + 95.994 = 180.156 g/mol."
        ],
        "result": "Glucose, C6H12O6, has a molar mass of 180.156 g/mol, and is 53.3% oxygen by mass."
    },
    "interpretation": "Use the molar mass to convert between grams and moles (moles = grams ÷ molar mass), for example when making up a solution in the Molarity Calculator.",
    "assumptions": [
        "Atoms have their natural isotopic composition. Atomic weights are the CIAAW abridged standard values (2024 edition)."
    ],
    "limitations": [
        "Elements with no stable isotopes (such as technetium or plutonium) have no standard atomic weight and are rejected.",
        "Charges and isotopic labels (e.g. D for deuterium) are not supported.",
        "Five significant figures are enough for laboratory work but not for high-precision mass spectrometry."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Is molecular weight the same as molar mass?",
            "answer": "Numerically, yes. Molecular weight is the mass of one molecule in daltons (u); molar mass is the mass of one mole in g/mol, and the two numbers are equal."
        },
        {
            "question": "Why do different tables give slightly different values?",
            "answer": "Some elements’ atomic weights vary with the source of the sample, so tables round them differently. The differences are usually in the third decimal place."
        }
    ],
    "sources": [
        {
            "title": "CIAAW — Abridged Standard Atomic Weights",
            "url": "https://ciaaw.org/abridged-atomic-weights.htm"
        }
    ],
    "related": [
        {
            "name": "Molarity Calculator",
            "url": "https://calculators.geekmidst.com/calculators/molarity-calculator"
        },
        {
            "name": "Density Calculator",
            "url": "https://calculators.geekmidst.com/calculators/density-calculator"
        },
        {
            "name": "Percentage Calculator",
            "url": "https://calculators.geekmidst.com/calculators/percentage-calculator"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}