Math
Large Number Unit Converter (Japanese–English)
Enter a number to see it expressed in both Japanese units (万, 億, 兆) and English units (million, billion, trillion). Includes a quick-reference table and real-world scale examples to clear up the "1億 = 1 million?" confusion.
Conversion tips
- When you see "億" (10^8), the English is hundred million. "1億円 = 1 million yen" is a common mistake — the correct translation is 100 million yen.
- "10億" = 1 billion. When you hear "a billion dollars" in English news, think of it as 10億ドル in Japanese.
- "1兆" = 1 trillion (= 10^12). This unit lines up in both languages. Japan's national budget is about 110兆円; the US GDP is roughly 25 trillion dollars.
- "100万" = 1 million (= 10^6). "Million" only appears at the 1,000,000 mark.
Side Note — Why the 4-digit vs 3-digit gap exists
The Japanese large-number system, inherited from ancient China, uses a myriad-based (万進法) system — units change every four digits: 万, 億, 兆, 京… Standard English uses a thousand-based system — thousand, million, billion… As a result, 10,000 (1万) has no single English word and must be written as "ten thousand."
The confusion is especially common in business and media. "How much is 10億円?" — since 10億 = 10^9 = 1 billion, the answer is "1 billion yen." A frequent error is translating 1億円 as "1 million yen," when the correct expression is "100 million yen." Use this converter to get it right every time.