Decimalkomma

Decimalkomma, or decimal comma, is the decimal separator used in many European and other locales to separate the integer part from the fractional part of a number. It is the comma character, not a period, and is read as the fractional separator in those regions rather than as a punctuation mark for a decimal point as in English.

Regional usage includes Dutch, German, French, Italian, Spanish, Portuguese, Swedish, Danish, Norwegian, Polish, Czech, Hungarian, Romanian and many other languages. In these conventions, 3,14 denotes three and fourteen hundredths, and 1 234,56 denotes one thousand two hundred thirty-four and fifty-six hundredths. The thousands separator is often a space or non-breaking space, rather than a comma.

In computing and data interchange, numeric formatting depends on locale. Returning numbers in the wrong format can cause misinterpretation, so software often supports locale-aware formatting and conversion. For machine processing, invariant representations such as the decimal point (as used in JSON and many programming contexts) or explicit locale settings are commonly employed to avoid ambiguity.

Historically, the decimal comma has roots in the development of the decimal numeral system and became standard in much of continental Europe during the early modern period, contrasting with the decimal point favored in English-speaking regions. Today, the decimal comma remains a key element of numerical notation in many countries, reflecting linguistic and cultural conventions in everyday writing and official documents.