Japanese months are beautifully regular: number + 月 (gatsu). Done. But when it comes to "what day of the month," things take a sharp turn — the 1st through the 10th use almost entirely irregular readings. This article covers both months and dates in one go.
〜月: Months
"Which month" is simply number + 月 (gatsu). The readings are completely regular with no exceptions:
| Month | Japanese | Reading |
|---|---|---|
| January | 一月 | いちがつ |
| February | 二月 | にがつ |
| March | 三月 | さんがつ |
| April | 四月 | しがつ |
| May | 五月 | ごがつ |
| June | 六月 | ろくがつ |
| July | 七月 | しちがつ |
| August | 八月 | はちがつ |
| September | 九月 | くがつ |
| October | 十月 | じゅうがつ |
| November | 十一月 | じゅういちがつ |
| December | 十二月 | じゅうにがつ |
| What month? | 何月 | なんがつ |
Watch out for three tricky ones: April = しがつ (not よんがつ), July = しちがつ (not なながつ), September = くがつ (not きゅうがつ).
〜日: Days of the Month
"What day" uses 〜日. The 1st through the 10th have massively irregular readings — this is one of the toughest things to memorize at the N5 level.
| Date | Japanese | Reading | Notes |
|---|---|---|---|
| 1st | 一日 | ついたち | Completely irregular |
| 2nd | 二日 | ふつか | Irregular |
| 3rd | 三日 | みっか | Irregular |
| 4th | 四日 | よっか | Irregular |
| 5th | 五日 | いつか | Irregular |
| 6th | 六日 | むいか | Irregular |
| 7th | 七日 | なのか | Irregular |
| 8th | 八日 | ようか | Irregular |
| 9th | 九日 | ここのか | Irregular |
| 10th | 十日 | とおか | Irregular |
| 14th | 十四日 | じゅうよっか | Uses the 4th pattern |
| 20th | 二十日 | はつか | Irregular |
| 24th | 二十四日 | にじゅうよっか | Uses the 4th pattern |
| What day? | 何日 | なんにち |
From the 11th onward (except 14th, 20th, and 24th), it's regular: number + にち. For example, 十一日 = じゅういちにち, 十五日 = じゅうごにち.
Memorization Tips
The readings for the 1st through the 10th come from the old native Japanese counting system (Yamato words), completely different from modern Sino-Japanese numbers. There's no shortcut — just repeat them:
ついたち・ふつか・みっか・よっか・いつか・むいか・なのか・ようか・ここのか・とおか
Try saying them three times a day for a week. Pay special attention to 20th = はつか, the only irregular one after the 10th.
Using Dates in Sentences
Asking someone's birthday:
お誕生日は何月何日ですか。 → When is your birthday?
Answering:
十月三十一日です。 → It's October 31st.
Asking today's date:
今日は何月何日ですか。 → What is today's date?
Answering:
二月十三日です。 → It's February 13th.
Combining date and day of the week:
木村先生の誕生日は十月三十一日、金曜日です。 → Mr. Kimura's birthday is October 31st, a Friday.
Using に with Dates
To say "on a certain date," add the particle に:
三月五日に日本へ行きます。 → I'm going to Japan on March 5th.
十二月二十五日にパーティーがあります。 → There's a party on December 25th.
However, 今日 (today) and 明日 (tomorrow) don't take に — the same rule as with other time expressions.
Summary
- Months = number + 月 (gatsu). Watch out for April (しがつ), July (しちがつ), September (くがつ)
- The 1st through 10th are all irregular — you must memorize them. The 20th (はつか) is also an exception
- From the 11th onward, most are regular: number + にち. The 14th and 24th follow the「よっか」pattern
- Ask dates with 何月何日ですか; add お誕生日は for birthdays
- Use particle に to say "on a certain date"
Practice Quiz
Q1. Say "April 8th" in Japanese.
Show Answer
四月八日 (しがつようか)
April = しがつ (not よんがつ), 8th = ようか (irregular reading).
Q2. What is the reading of 「九月二十日」?
Show Answer
くがつはつか
September = くがつ (not きゅうがつ), 20th = はつか (special reading).
Q3. Translate into Japanese: "My birthday is March 3rd."
Show Answer
誕生日は三月三日です。 (たんじょうびは さんがつ みっか です。)
March = さんがつ, 3rd = みっか (irregular reading).