The Complete Guide to Japanese Number Systems

Understanding Japanese numbers is fundamental to mastering the language, yet it's one of the most complex aspects for learners. Unlike English, Japanese uses multiple number systems, special counters, and unique readings that change based on context.

Three Ways to Write Numbers in Japanese

Japanese employs three distinct methods for writing numbers, each with specific use cases:

1. Arabic Numerals (1, 2, 3)

Just like in English, Japanese uses Arabic numerals extensively in:

• Modern documents and forms
• Prices and mathematical calculations
• Digital displays and keyboards
• Western calendar dates

2. Kanji Numbers (一、二、三)

Traditional Chinese characters used for:

• Formal documents and contracts
• Traditional contexts and ceremonies
• Vertical writing
• Bank documents (special formal versions)

3. Hiragana Numbers (いち、に、さん)

Phonetic writing used for:

• Children's books
• Language learning materials
• When emphasizing pronunciation

Basic Numbers 1-10

| Number | Kanji | Hiragana | Romaji | English | |--------|-------|----------|---------|---------| | 1 | 一 | いち | ichi | one | | 2 | 二 | に | ni | two | | 3 | 三 | さん | san | three | | 4 | 四 | よん/し | yon/shi | four | | 5 | 五 | ご | go | five | | 6 | 六 | ろく | roku | six | | 7 | 七 | なな/しち | nana/shichi | seven | | 8 | 八 | はち | hachi | eight | | 9 | 九 | きゅう/く | kyuu/ku | nine | | 10 | 十 | じゅう | juu | ten |

Important Note: Alternative Readings

Numbers 4, 7, and 9 have two readings:

• 4: よん (yon) is preferred; し (shi) sounds like "death"
• 7: なな (nana) is common; しち (shichi) used in compounds
• 9: きゅう (kyuu) is standard; く (ku) sounds like "suffering"

Counting Beyond 10

Tens (10-90)

• 20: 二十 (にじゅう, nijuu)
• 30: 三十 (さんじゅう, sanjuu)
• 40: 四十 (よんじゅう, yonjuu)
• 50: 五十 (ごじゅう, gojuu)

Hundreds (100-900)

• 100: 百 (ひゃく, hyaku)
• 200: 二百 (にひゃく, nihyaku)
• 300: 三百 (さんびゃく, sanbyaku) *
• 600: 六百 (ろっぴゃく, roppyaku) *
• 800: 八百 (はっぴゃく, happyaku) *

*Note the pronunciation changes!

Thousands and Beyond

• 1,000: 千 (せん, sen)
• 10,000: 万 (まん, man)
• 100,000,000: 億 (おく, oku)

The 10,000 Grouping System

Unlike Western counting (thousands), Japanese groups by 10,000s:

• 10,000 = 1万 (ichiman)
• 100,000 = 10万 (juuman)
• 1,000,000 = 100万 (hyakuman)

Japanese Counters: The Complex Part

Japanese uses specific counters for different types of objects. Here are essential ones:

Common Counters

| Counter | Usage | Example | |---------|--------|----------| | つ (tsu) | General objects | 一つ (hitotsu) - one thing | | 本 (hon) | Long objects | 二本 (nihon) - two bottles | | 枚 (mai) | Flat objects | 三枚 (sanmai) - three sheets | | 個 (ko) | Small objects | 四個 (yonko) - four pieces | | 人 (nin) | People | 五人 (gonin) - five people | | 匹 (hiki) | Small animals | 六匹 (roppiki) - six animals | | 冊 (satsu) | Books | 七冊 (nanasatsu) - seven books | | 台 (dai) | Machines/vehicles | 八台 (hachidai) - eight cars |

Special Readings with Counters

When numbers combine with counters, pronunciation often changes:

• 一人 (hitori) - one person (not ichinin)
• 二人 (futari) - two people (not ninin)
• 三本 (sanbon) - three bottles (not sanhon)

Practical Applications

Telling Time

• 1時 (ichiji) - 1 o'clock
• 2時半 (nijihan) - 2:30
• 3時15分 (sanji juugofun) - 3:15

Dates

• 1月 (ichigatsu) - January
• 2日 (futsuka) - 2nd day
• 2025年 (nisenjuugonen) - Year 2025

Money

• 100円 (hyakuen) - 100 yen
• 1,000円 (sen'en) - 1,000 yen
• 10,000円 (ichiman'en) - 10,000 yen

Ages

• 20歳 (hatachi/nijussai) - 20 years old
• 30歳 (sanjussai) - 30 years old

Tips for Learning Japanese Numbers

1. Master basic 1-10 first - Everything builds from here
2. Learn counters gradually - Start with つ (tsu) for general counting
3. Practice with real scenarios - Shopping, time, dates
4. Pay attention to sound changes - Especially with hundreds
5. Use number converters - Tools help verify your understanding

Common Mistakes to Avoid

• Using し (shi) for 4 in casual contexts
• Forgetting counter words entirely
• Applying Western grouping (thousands) instead of 万 (ten thousands)
• Ignoring special readings for 20 years old (はたち hatachi)

Formal vs. Casual Number Usage

Formal Numbers (大字)

Banks and legal documents use special kanji to prevent forgery:

• 一 → 壱 (ichi)
• 二 → 弐 (ni)
• 三 → 参 (san)
• 十 → 拾 (juu)

Phone Numbers

Spoken as individual digits:

• 03-1234-5678 = ゼロ さん の いち に さん よん の ご ろく なな はち

Conclusion

Japanese numbers may seem overwhelming initially, but they follow logical patterns. Start with basic counting, gradually add counters, and practice in real-life contexts. Whether you're shopping in Tokyo, reading manga, or converting dates, understanding Japanese numbers opens doors to deeper language comprehension.

Remember: even native speakers occasionally struggle with complex counter combinations. Don't aim for perfection—focus on clear communication and gradual improvement.

For instant number conversion and practice, try our Japanese Number Converter tool to see how different numbers are written and pronounced in various contexts.