0 in Japanese = 零 / ゼロ (rei / zero)

The number 0 in Japanese has two main forms: 零 (rei) pronounced "ray" (native Japanese reading) and ゼロ (zero) pronounced "ZEH-roh" (borrowed from English). The katakana ゼロ is more commonly used in everyday speech.

Quick Answer

Pronunciation

Rei (零/れい):

• One syllable: rei
• Pronounced like English "ray"
• More formal, traditional reading
• Used in specific contexts

Zero (ゼロ):

• Two syllables: ze-ro
• Pronounced "ZEH-roh" (like English "zero" but with short vowels)
• More common in everyday speech
• Katakana indicates it's a loan word from English

Common mistakes:

• Pronouncing ゼロ with long vowels like English "zero"—Japanese vowels are shorter
• Not knowing which form to use in different contexts
• Pronouncing rei as "ray-ee" (two syllables)—it's one syllable

The Words for Zero

零 (rei):

• Kanji character meaning "zero"
• Traditional Chinese-derived reading
• More formal and literary
• Used in temperature, mathematics

ゼロ (zero):

• Katakana spelling (borrowed from English)
• Most common in daily conversation
• Used in phone numbers, scores, counting

When to Use Each Form

Use 零 (rei):

• Temperature: 零度 (reido) = 0 degrees
• Mathematical contexts: 零点 (reiten) = zero point
• Formal writing
• Time (sometimes): 零時 (reiji) = midnight/0:00

Use ゼロ (zero):

• Phone numbers: 090-0000-0000
• Counting: ゼロ、いち、に、さん (zero, ichi, ni, san)
• Sports scores: 3対ゼロ (3 tai zero) = 3-0
• General conversation
• Room numbers, addresses

Practical Usage

Phone numbers: Each digit is pronounced separately, almost always using ゼロ:

• 0 = ゼロ (zero)
• Example: 090 = ゼロきゅうゼロ (zero kyū zero)

Prices:

• ¥0 = ゼロ円 (zero en) - though this is rare
• Typically, zero doesn't appear in prices as standalone

Times:

• 0:00 = 零時 (reiji) or 午前零時 (gozen reiji) = midnight
• Also: 真夜中 (mayonaka) = midnight
• Can also say 12時 (jūni-ji) for midnight

Dates:

• Zero doesn't appear in dates (days start from 1st)

Temperature:

• 0°C = 零度 (reido) or ゼロ度 (zero do)
• Below zero: 零下 (reika) or マイナス (mainasu) = minus

Addresses:

• Room 0 would be ゼロ号室 (zero gōshitsu) if it exists (rare)

Counting and Numbers

When counting from zero:

• ゼロ、いち、に、さん、し/よん、ご... (zero, ichi, ni, san, shi/yon, go...)
• ゼロ is much more common than 零 in counting

Compound numbers:

• 10 = 十 (jū), not "one-zero"
• 100 = 百 (hyaku), not "one-zero-zero"
• Zero only appears as a digit in numbers like 101 (百一 hyaku ichi), 102, etc.
• Though in some modern contexts: 101 can be いちゼロいち (ichi zero ichi)

Writing

Kanji: 零

• Complex character with 13 strokes
• Rarely handwritten in casual contexts
• More common to use ゼロ

Hiragana: れい

• Two characters: れ (re) + い (i)
• Less common than katakana

Katakana: ゼロ

• Two characters: ゼ (ze) + ロ (ro)
• Most common written form
• Used in casual and modern contexts

Common Phrases and Expressions

ゼロから始める (zero kara hajimeru): Start from zero, start from scratch

ゼロサム (zero samu): Zero-sum (from English)

零細企業 (reisai kigyō): Very small enterprise (using 零 meaning "tiny/minute")

零下 (reika): Below zero (temperature)

零点 (reiten): Zero points

ゼロに等しい (zero ni hitoshii): Equal to zero, virtually nothing

Grammar Notes

Counters: Zero can be used with various counters:

• ゼロ個 (zero ko) = zero items
• ゼロ人 (zero nin) = zero people
• However, often the negative form is used instead: いない (inai) = there aren't any

In mathematics:

• 0 + 5 = 5: ゼロたすご は ご (zero tasu go wa go)
• 5 - 5 = 0: ごひくご は ゼロ (go hiku go wa zero)

Cultural Note

Unlike numbers 4 (し - shi, sounds like "death") and 9 (く - ku, sounds like "suffering") which are considered unlucky, zero has no particular superstitious associations in Japanese culture.

Quick Takeaways

• 0 in Japanese has two forms: 零 (rei) and ゼロ (zero)
• ゼロ is more common in everyday speech and is borrowed from English
• 零 (rei) is more formal, used for temperature and mathematical contexts
• Phone numbers and counting use ゼロ
• Midnight can be 零時 (reiji)
• No cultural superstitions associated with zero
• ゼロ is written in katakana (loan word)
• Pronounced "ray" (rei) or "ZEH-roh" (zero) with short vowels

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If you're traveling in Japan and need to hear numbers in context, TravelNum shows you exactly how any number is pronounced in Japanese.