Translation guide
How to express a number of years in Japanese, depending on context: duration, age, or a specific year count.
Expressing a period of time lasting a certain number of years.
The most common way to say 'N years' as a duration. The counter 年 (ねん) follows the number. Works for any number of years.
I have lived in Japan for three years.
This project took five years.
Explicitly emphasizes the duration. Often used when the time span is the focus, or to avoid ambiguity with a specific year (e.g., 2020年).
He worked as a teacher for ten years.
Emphasizes a long duration, often with a sense of 'as long as N years'. Used for highlighting the length of time.
She has been working at this company for as long as twenty years.
Stating someone's age in years.
The standard counter for age. Note the irregular readings for 1 (いっさい), 8 (はっさい), 10 (じゅっさい/じっさい), 20 (はたち).
My daughter will be six years old this year.
My grandfather is 90 years old.
A simplified, informal variant of 歳, often used in casual writing or when the kanji is too complex. Same reading.
He's still only 20 years old.
Referring to a number of years as a quantity, such as in statistics or comparisons.
Means 'number of years' as a noun. Used in formal or technical contexts.
The required number of years of service is three.
A formal written pattern meaning 'N years'. Often used in reports or official documents.
This is a five-year plan.
年 (ねん) alone can mean both a specific year (e.g., 2020年) and a duration. Adding 間 (かん) makes it unambiguously a duration. Use 年間 when you want to emphasize the length of time, especially in sentences where 年 might be misinterpreted.
He was in Japan for three years. (Could also be interpreted as 'He was in Japan in the year 3' in some contexts, though unlikely.)
He was in Japan for three years. (Clearly duration.)
When talking about age, always use 歳 (さい) or 才 (さい). Using 年 (ねん) for age is incorrect and would mean 'year' as in calendar year.
(Incorrect for age; would mean 'He is the year 10' or similar.)