Currency Formatter

How to format numbers as currency?

Currency formatting follows locale-specific conventions that vary dramatically across countries. Here's exactly how to get properly formatted output:

• Enter the numeric amount you want to format in the input field. You can type whole numbers like 1000, decimals like 99.99, negative values like -50.25, or large values like 1500000.
• Select your target currency from the dropdown — choose from all ISO 4217 codes including USD (US Dollar), EUR (Euro), JPY (Japanese Yen), VND (Vietnamese Dong), and over 200 others.
• Choose a locale/region for formatting conventions. The locale determines decimal separators, thousands separators, and currency symbol placement. For example, en-US formats as '$1,234.56' while de-DE formats as '1.234,56 €' while vi-VN formats as '1.234,56 ₫'.
• Optionally adjust minimum and maximum decimal places. Most currencies use 2 decimals, but Japanese Yen uses 0, Kuwaiti Dinar uses 3, and Vietnamese Dong typically uses 0 despite having subunits.
• Copy the formatted string using the copy icon. The result is ready to paste into invoices, reports, UI mockups, or code files with correct localization applied.

Why currency formatting varies so much across locales

The Intl.NumberFormat API (part of ECMAScript Internationalization API) handles currency formatting by consulting Unicode CLDR (Common Locale Data Repository) data for each locale. This data encodes country-specific rules that go far beyond simple symbol substitution. In the US, the dollar sign precedes the number with no space ($100). In France, there's a non-breaking space between the number and euro sign (100 €). In Germany, commas separate thousands and periods separate decimals (1.234,56 €). In India, the lakhs system groups digits differently after the first three: 1,23,456.78 instead of 123,456.78. Some locales like Switzerland use multiple currency symbols depending on the region (CHF for German-speaking, Franc Suisse for French-speaking). The currency display symbol option shows localized symbols (€ vs EUR), while the code option always shows the ISO code. Understanding these nuances prevents embarrassing mistakes in international applications — displaying '1.000.000 €' to a German user clearly means one million euros, but an American reader might interpret it as one thousand euros.

Common pitfalls when formatting currency in applications

• Rounding errors: JavaScript's floating-point arithmetic can produce results like 19.995000000000002. Always round to the appropriate decimal places before formatting — use Math.round(value * 100) / 100 for 2-decimal currencies.
• Zero-decimal currencies: JPY, KRW, VND, and several others don't use fractional units. Formatting 1000 JPY with 2 decimal places produces '¥1,000.00' which looks unprofessional. Set minimumFractionDigits and maximumFractionDigits to 0 for these currencies.
• Negative number display: Different locales place the minus sign differently. en-US shows '-$100', fr-FR shows '-100,00 €', and some Asian locales may use a leading minus without space. Let the locale handle this automatically rather than hardcoding.
• Currency symbol vs code: Using style:'currency' shows the localized symbol (€), while style:'decimal' with currencyCode shows the ISO code (EUR). Choose based on your audience — consumer-facing apps benefit from symbols, while backend systems often prefer codes.
• Missing locale support: Not all browsers implement full ICU data. Older browsers or minimal builds may fall back to default formatting. Test your target locales across browsers, especially for right-to-left locales like ar-SA where the currency symbol appears on the left.