Grammar Info

N3 Lesson 8: 8/22


Repeated at intervals, Every other, Every, At intervals of


Number + Counter + おきに


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About おきに

While ()きに may appear to be an adverb, it is actually a combination of ()き, a suffix meaning 'opening', and the case marking particle に. ()きに (often without kanji) is an expression used to show that something happens 'every (A)', or 'at intervals of (A)'.
As おきに is technically a suffix, it will be attached to the end of numbers or counters that it is highlighting as being an 'opening'.
  • この(くすり)一日(いちにち)おきに()んでください。
    Please drink this medicine every other day. (Every second day)
  • ()(げつ)おきに病院(びょういん)()ように先生(せんせい)()われました。
    I was told by the doctor to come to the hospital every other month. (Every second month)
  • 二日(ふつか)おきに部屋(へや)掃除(そうじ)ないと()()()かない
    I can't relax if I don't clean my room every three days.
It is very common to get ごとに, and おきに mixed up. While ごとに has the literal meaning of 'every', おきに has the literal meaning of 'opening'. Due to this, おきに will not always mean 'every'. Let's look at some examples of when these two expressions are the same, and when they are not.
Discrete variables (things that are usually measured upon completion) - Only ごとに may be used to express 'every'. For example, a day, a week, or a month may easily be divided, but they are usually counted as whole units. Due to this, ごとに will mean 'every week', while おきに would actually mean 'every second week' (because there is an opening of one week).
  • 一日(いちにち)おきに目薬(めぐすり)()す。
    I use my eye drops every other day.
  • (わたし)()かけるおきに(わす)(もの)する
    Every other time I go out, I forget something.
Continuous variables (things that are usually measured in fractions) - Either ごとに or おきに may be used. For example, seconds, minutes, and hours are usually measured by fractions, especially considering sports and racing. In this case ごとに will mean 'every second', while おきに will mean 'every opening of one second' (disregarding all of the milliseconds, this means every second).
  • 毎日(まいにち)2時間(じかん)ごとに(からだ)(うご)かしている
    I move my body every 2 hours, everyday.
  • 毎日(まいにち)2時間(じかん)おきに(からだ)(うご)かしている
    I move my body every other 2 hours, everyday.
Fun Fact
This is a topic that native speakers frequently get wrong themselves, so don't worry if it is a bit tricky! If you are unsure about which one to use, think of ()きに as 'every other' for most purposes.


  • 1時間(じかん)おきに温度(おんど)(はか)ってください。

    Please check the temperature every other hour.

    At intervals of 1 hour. Interchangeable with 1時間ごとに.

  • 1週間(しゅうかん)おきに水槽(すいそう)(みず)()えています。

    We change the water of the fish tank every other week.

    At intervals of 1 week event happens every other week. Not interchangeable with 1週間ごとに, but 2週間ごとに can be used.

  • 30(ぷん)おきに休憩(きゅうけい)しよう。

    Let's take a break in intervals of 30 minutes.

  • 金魚(きんぎょ)には(えさ)一日(いちにち)おきにやればいいらしい。

    I've heard that you can feed goldfish every second day.

  • この地域(ちいき)はだいたい一軒(いっけん)おきに新聞(しんぶん)をとっている。

    In this area, every other house is subscribed to the newspaper.

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おきに – Grammar Discussion

Most Recent Replies (24 in total)

  • albcasahu


    About 1 month ago

    I have the exact same question. It also says that it is interchangeable with ごとに in this context, so I assume that it should be every hour instead. I keep getting this grammar point wrong and it’s driving me crazy

  • Inounx


    About 1 month ago

    Hi, my teacher (native japanese) told me that it is every hour, yes. Other native people also confirmed this. It is a translation mistake.

  • nekoyama


    About 1 month ago

    With おきに the meaning is always a bit unclear, and 1時間おきに is probably the most unclear case. For either interpretation, you can find native speakers who support it.

    Related: ~おきに | ことば(放送用語) - 最近気になる放送用語 | NHK放送文化研究所

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