Desimaalierotin

Desimaalierotin, in Finnish, refers to the decimal separator, the symbol used to separate the integer part from the fractional part of a decimal number written in decimal notation. The two most common decimal separators are the period (.) and the comma (,).

The choice of symbol is largely regional and language-dependent. In English-speaking countries and many others, the decimal point (.) is used, as in 1234.56. In many European and several other locales, the decimal comma (,) is used, as in 1 234,56, with variations in how thousands are grouped or spaced. Some locales also employ a space as a thousands separator, which can influence the appearance of numbers in printed text.

In computing and data formats, the period is the standard decimal separator in most programming languages and data formats (for example, in source code and JSON). The comma is rarely used as a decimal separator in programming, though it can appear as a delimiter in certain contexts or locales (for example, in some CSV files). To avoid ambiguity in cross‑locale data exchange, numbers are often represented with a fixed decimal point or the locale is explicitly specified.

Standards and localization systems, such as Unicode CLDR, provide locale-specific rules for decimal and thousands separators. When presenting numeric data internationally, it is common to indicate the locale or to use a format that avoids ambiguity, such as using the period as the decimal separator in technical contexts.