‘十亿’ (shí yì) literally means ‘ten hundred-million’ and equals one billion (10⁹ or 1,000,000,000) in the Chinese numeral system. Unlike English, which uses ‘billion’ for 10⁹, traditional Chinese counting is based on myriads: 万 (wàn) = 10⁴, 亿 (yì) = 10⁸, so 十亿 = 10 × 10⁸ = 10⁹. This term is used exclusively for large quantities — population figures, national budgets, corporate revenues, or scientific measurements — and always functions as a numeral, not a noun on its own.

In spoken and written Chinese, 十亿 is standard in mainland China and Singapore, while Taiwan and some overseas communities may occasionally use ‘十億’ (traditional characters) but retain the same pronunciation and meaning. It appears in formal contexts like news reports, economic data, and official statistics, and is never used colloquially to exaggerate small amounts — doing so would sound unnatural or humorous.