for one's age; considering one's age
Used to express that something is unexpected or noteworthy relative to a person's age. Often followed by a statement of surprise or contrast.
He looks young for his age.
She has well-formed opinions for her age.
Standard kanji spelling.
Kana spelling of 割; common in casual writing.
Uses 歳, which specifically means 'age'.
Phrase composed of 年 (year/age), の (possessive particle), 割 (proportion/ratio), and に (adverbial particle). Literally 'in proportion to one's age'.