Number Formatting
Displaying numbers according to locale-specific conventions.
Definition
Number formatting varies by locale: decimal separators (. vs ,), thousand separators (. vs , vs space), digit grouping, and more. Currency formatting adds symbol position and spacing. The JavaScript Intl.NumberFormat API handles locale-aware number and currency formatting automatically. Proper number formatting prevents confusion and errors in financial and data applications.
Examples
- →US: 1,234.56
- →Germany: 1.234,56
- →France: 1 234,56 (space separator)
- →Currency: $1,234.56 (US) vs 1.234,56 € (Germany)
Frequently Asked Questions
How do I format currency correctly?
Use Intl.NumberFormat with style: 'currency' and currency code. Example: new Intl.NumberFormat('de-DE', {style: 'currency', currency: 'EUR'}).format(1234.56) → '1.234,56 €'. Always specify currency code, not just locale.
Should I store formatted or raw numbers?
Always store raw numbers (1234.56 as Number or Decimal). Format only for display. Never store formatted strings—you lose precision and can't reformat for other locales. Parse user input to raw numbers immediately.