An Introduction

A number consists of the integer part and decimal part, separated by the decimal symbol. The integer part may be separated by the grouping symbol (sometimes called the thousand symbol), which makes long numbers easier to read.

In the United States, we use a period for the decimal symbol and a comma for the grouping symbol.

Decimal Symbols

The three different decimal symbols are the comma, the period, and the arabic decimal separator.

Grouping Symbols

The six different grouping symbols are the comma, the period, a space, a narrow space, the arabic thousands separator, and the right quotation mark.

Grouping Patterns

The most common pattern for grouping is every 3 digits. But some locales in and around India use a unique 2-digit grouping system.

Here is what the number 1 billion looks like with both grouping patterns, and a comma as the grouping symbol.

Notice that the 2-digit grouping still uses 3 digits for the right-most group, but groups by 2 digits for everything else.

Distinct Formatting Patterns

Here are the different combinations of formatting patterns across all supported locales:

Minus Signs

There are two different symbols used for minus signs. The hyphen is used in most locales, but there is a longer minus sign symbol that is used as well.

Numbering Systems

The numbers 0-9 are called arabic numerals, latin numerals, or western numerals.

The term arabic numerals can be confusing, because although they invented the number system, they no longer use it.

Here is a small sample of common numbering systems, but there are many others:

See the full list of numbering systems.

Further Reading

See the number formatting guide for formatting numbers in javascript.

See the number parsing guide for parsing numbers in javascript.