Japan Number Format
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Format Rules
Japan formatting implementation notes
For Japan, format numbers with the explicit locale ja-JP; the reference value 1234567.89 renders as 1,234,568.
Japan's reference format uses "." as the decimal mark and comma (",") for grouping. The integer uses repeating groups of three digits. Pass "ja-JP" directly to Intl.NumberFormat instead of replacing punctuation in a preformatted string.
JPY is shown with ¥ immediately before the amount; the same reference value renders as ¥1,234,568. The percent sign appears immediately after the amount. Use the ISO currency code for storage and interchange because a visible symbol can be shared by unrelated currencies.
Western 0–9 digits are the page's reference digit system, and the negative pattern is -n. Treat ja-JP as the reference locale for this page, but still respect the user's explicitly selected language and numbering-system preferences. Validate output with formatToParts() when spacing, signs, or bidirectional literals affect the interface.
- Locale: ja-JP
- Decimal and grouping: 1,234,568
- Currency: JPY → ¥1,234,568
- Digits: Western 0–9 digits
Reviewed 19 July 2026. Sources: Unicode locale number formats · Intl.NumberFormat reference
Code Examples
// Basic number
new Intl.NumberFormat('ja-JP').format(1234567.89)
// → "1,234,568"
// Currency
new Intl.NumberFormat('ja-JP', {
style: 'currency',
currency: 'JPY'
}).format(1234567.89)
// → "¥1,234,568"
// Percentage
new Intl.NumberFormat('ja-JP', {
style: 'percent',
minimumFractionDigits: 1
}).format(0.125)
// Compact notation
new Intl.NumberFormat('ja-JP', {
notation: 'compact'
}).format(1234567)Negative Number Formats
new Intl.NumberFormat('ja-JP').format(-1234567.89)new Intl.NumberFormat('ja-JP', { style: 'currency', currency: 'JPY', currencySign: 'accounting' }).format(-1234567.89)Edge Cases & Notes
JPY has 0 minor units. Compact uses 万 (man=10,000) and 億 (oku=100,000,000) — very different from Western compact.
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