In pinyin the tone mark (diacritical mark) only goes on vowels.

If there is only one vowel in a character's pinyin then the answer is easy, the tone mark just goes on the vowel. For example:

思 sī, 于 yú, 鼠 shǔ, 指 zhǐ

If there is more than one vowel in the character's pinyin, then the tone mark goes on one of the vowels, but is there a rule to decide which vowel it goes on? For example:

手 shǒu, 想 xiǎng, 短 duǎn, 率 shuài

You can see from the examples that it is not always on the first vowel, or always on the last vowel.

For a while I thought it might be that the tone mark goes on alphabetically the first vowel in the character's pinyin, ie. if the character has 'a' then put it on 'a', if the character doesn't have 'a' but has 'e' then put it on 'e', if it doesn't have 'e' but has 'i' then put it on 'i', etc. But I found some counter examples to this:

丢 diū, 留 liú, 久 jiǔ

Is there a rule that determines where to put the tone mark?

I am asking because I want to convert between pinyin of the form with numbers (eg. bing3, tong2, suan1) to the format with diacritics without having to use huge lookup tables.


4 Answers 4


when I was in primary school,My teacher always told us a mnemonic rhyme.



The simple rule is that it goes on the first match in this list: a; o; e; the last i or u.

As to why this is the case, the tone mark should go on the sustained vowel sound. This is the reason of i and u breaking the aoeiu order - iu and ui are actually contractions of iou and uei.


You are close. It does go alphabetically, but the alphabet isn't the English one. Well, why should it follow the English alphabet anyway?

If there are two or three vowel letters, the tone mark is placed above the vowel listed earliest in this sequence: a o e i u ü.

BTW, you have a very nice screen name :)

  • 3
    Haha thanks. There is one exception though, if the pinyin contains iu then the tone mark is placed on the u and not the i, see the link in my comment on the original post.
    – F Chopin
    Apr 21, 2022 at 16:22
  • 1
    @FChopin I never noticed that. As they say, you live to learn. Thanks.
    – monalisa
    Apr 21, 2022 at 18:26
  • 1
    It is not a fixed sequence: guì (贵) vs liù (六)
    – fefe
    Apr 22, 2022 at 7:52
  • 1
    @fefe, "guì" is really "guèi". Similarly, "iū" is really "iōu". Pinyin has "simplified" spelling like this that actually makes things more complicated, and causes the rest of the world to mispronounce it. "Fung Shoo-EE" anyone? Apr 22, 2022 at 20:53

When a plain pronunciation connects to multiple words, the tone mark is to be placed on where the emphasis to be, which is the vowel that changes the sound/way of pronunciation.

  • 手[shǒu] 受[shòu] 熟[shóu] 收[shōu]
  • 想[xiǎng] 詳[xiang] 相[xiàng,xiāng]
  • 短[duǎn] 斷[duàn] 端[duān]
  • 率[shuài] 摔[shuāi] 甩[shuǎi]
  • What does "the vowel that changes the sound/way of pronunciation" mean? In your first example, how does /o/ changes the sound, but not /u/? And what is the sound that gets changed? Same question with all the other examples you listed.
    – monalisa
    Apr 21, 2022 at 18:25
  • @monalisa You can try to pronounce these words with the tone marks (重音/輕音/平音/揚音) on "u" and find the words associated with those pronunciations.. I doubt there is any, but I could be wrong though.
    – r13
    Apr 21, 2022 at 18:51

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