～ついでに
while you’re at it
～ついでに links two actions: while doing the main one, you take the opportunity to also do a smaller, secondary one. It attaches to a noun + の or directly to a verb.
It maps to English “while you're at it” or “on the same occasion as”. The part before ついでに is the main purpose and what follows is the convenient extra.
1. Noun + のついでに
With an action noun, のついでに means “taking advantage of (that errand)”.
買い物のついでに郵便局へ行った。
“I went to the post office while I was out shopping.”
- 買い物（かいもの）= shopping
- の = links the noun to ついでに
- ついでに = while at it, on the same occasion
- 郵便局（ゆうびんきょく）= post office
- へ = direction marker
- 行った（いった）= went
2. Verb + ついでに
A verb attaches directly: dictionary form if the extra task happens along the way, た-form if it happens after the main action is already done.
出かけるついでにごみを出した。
“While going out, I took out the trash.”
- 出かける（でかける）= to go out
- ついでに = while at it
- ごみ = trash
- を = object marker
- 出した（だした）= took out
How to form it
Noun + の + ついでに / Verb (dictionary or た-form) + ついでに
- 買い物（かいもの）= shopping → 買い物のついでに（かいもののついでに）= while out shopping
- 行く（いく）= to go → 行くついでに（いくついでに）= while going
- 洗う（あらう）= to wash → 洗ったついでに（あらったついでに）= while (I) was at it washing
Key idea
～ついでに says: “I'm already doing X, so it costs me nothing extra to do Y too.” The main action comes first, the add-on rides along on the same occasion.
Other N3 grammar
Updated .