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    Not a Number (NaN)

    Reading time: 2 min.Editorially reviewed on:

    Definition

    NaN indicates an invalid result of certain numerical calculations.

    A special floating-point value for undefined or unrepresentable numerical results.

    Simply explained

    Instead of a usable number, a special marker appears: This calculation yields no valid numeric value here.

    Why it matters in practice

    Helps develop and operate digital systems robustly, securely, and maintainably.

    Example from business

    An operation like 0.0 divided by 0.0 typically produces NaN in IEEE-754 arithmetic and is checked before further calculation.

    Limits and pitfalls

    • Equate NaN with zero or missing data value; treat comparisons with NaN incorrectly.

    Origin & history

    NaN is defined in the IEEE-754 standard for floating-point arithmetic.

    Use in mid-sized companies

    • Possible application: An operation like 0.0 divided by 0.0 typically produces NaN in IEEE-754 arithmetic and is checked before further calculation.

    Frequently asked questions

    What does Invalid Number Value (NaN) mean?

    A special floating-point value for undefined or unrepresentable numerical results.

    Which mistakes should be avoided?

    Equate NaN with zero or missing data value; treat comparisons with NaN incorrectly.

    Sources

    Source checked on 10.10.2026. Editorial application examples are hypothetical; no evidence of real customer results.

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