How to tell them apart
毎 attaches as a prefix to a time word to mean every single unit without exception (毎食, 毎時), whereas ごとに follows a number-plus-counter noun and marks recurring events at fixed intervals, often with gaps in between (三日ごとに). Use 毎 for things that happen each and every time a unit occurs; use ごとに when an action repeats after a set span, not necessarily every day or hour. Saying 毎三日 is wrong because 毎 already implies every unit and cannot take a number.
- 毎・まい Use 毎 when something happens at every single instance of a time unit, like every meal or every hour.
- ごとに Use ごとに when an action repeats at fixed intervals, such as every third day or after each lesson.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| 毎・まい mai | Each; per unit | N5 |
| ごとに gotoni | each time, at every interval | N4 |
毎・まい mai
Each; per unit
まい attaches to the volitional form of a verb and pairs with 〜(よ)うと to mean 'whether or not' the action happens, as in 行こうと行くまいが. It can also follow the negative stem (おくれまい) in the same paired structure. The pattern appears in formal, written-style sentences.
-
金をもうけようともうけまいと、われわれは死ぬのだ。
We die whether we make money or not.
-
彼の来るのがおくれようとおくれまいとかまわない。
It doesn't matter whether he comes late or not.
ごとに gotoni
each time, at every interval
ごとに attaches to a noun (or a plain-form verb, as in 終えるごとに) to show that something happens at each occurrence of that noun or verb, or at regular intervals such as ４年ごとに. It is neutral in register and common in both speech and writing.
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私は仕事を一つ終えるごとにリストの上でチェックする。
I check off each task on my list as soon as I complete it.
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私たちはアメリカにいたころ日曜日ごとに教会へ行った。
We went to church every Sunday when we were in America.
毎・まい and ごとに are JLPT N5–N4 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.