{
    "name": "Percent Error Calculator",
    "url": "https://calculators.geekmidst.com/calculators/percent-error-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/percent-error-calculator.md",
    "category": "Mathematics",
    "description": "Work out the percent error between a measured or estimated value and the true, accepted value, plus the absolute error and its direction.",
    "summary": "Percent error tells you how far a measurement is from the accepted value, as a percentage of that accepted value.",
    "also_called": [
        "Percentage error calculator",
        "Relative error 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": "measured",
            "label": "Measured (experimental) value",
            "type": "number",
            "default": "52"
        },
        {
            "name": "accepted",
            "label": "True (accepted) value",
            "type": "number",
            "default": "50"
        }
    ],
    "outputs": [
        {
            "key": "percent_error",
            "label": "Percent error",
            "format": "percent"
        },
        {
            "key": "abs_error",
            "label": "Absolute error",
            "format": "number"
        },
        {
            "key": "signed_error",
            "label": "Signed percent error",
            "format": "percent"
        },
        {
            "key": "direction",
            "label": "Direction",
            "format": "text"
        }
    ],
    "formula": {
        "text": "Percent error = |Measured − True| ÷ |True| × 100",
        "variables": {
            "Measured": "the value you obtained",
            "True": "the accepted or reference value"
        }
    },
    "worked_example": {
        "inputs": {
            "measured": "52",
            "accepted": "50"
        },
        "steps": [
            "Absolute error = |52 − 50| = 2.",
            "Percent error = 2 ÷ 50 × 100 = 4%."
        ],
        "result": "Measuring 52 when the true value is 50 is a 4% error, on the high side."
    },
    "interpretation": "A small percent error means the result is accurate, not that it is precise: repeated measurements can all be close to each other and still share the same bias.",
    "assumptions": [
        "The true value is known and is not 0."
    ],
    "limitations": [
        "When the true value is 0 or very close to it, percent error is undefined or explodes; report the absolute error instead."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Can percent error be negative?",
            "answer": "The usual definition uses the absolute value, so it is never negative. Some lab courses keep the sign to show whether the result was high or low; the calculator shows both."
        },
        {
            "question": "Is percent error the same as percentage change?",
            "answer": "The arithmetic is similar, but percent error compares against a true value, while percentage change compares a new value against an old one."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Percentage Change Calculator",
            "url": "https://calculators.geekmidst.com/calculators/percentage-change-calculator"
        },
        {
            "name": "Percentage Calculator",
            "url": "https://calculators.geekmidst.com/calculators/percentage-calculator"
        },
        {
            "name": "Statistics Calculator",
            "url": "https://calculators.geekmidst.com/calculators/statistics-calculator"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}