How to say "billion" in Japanese

• 十億じゅうおくCommon
  numeralThe ordinary way to express the number 1,000,000,000. Use it whenever 'billion' appears in counting, prices, populations, or other numerical contexts; it reads じゅうおく.
• ビリオン
  nounA loanword matching the gloss 'billion', but a less common way to say it. For the number 1,000,000,000, 十億 is usually the word you want; reach for ビリオン only when the foreign-sounding form is deliberate.

For the number 1,000,000,000, use 十億; 「ビリオン」 is a less common loanword rendering of 'billion', so 十億 is the safe choice for ordinary counting contexts.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 十億じゅうおく1,000,000,000
• ビリオンbillion