There are a couple of different ways to express that you are happy in Thai. Let’s learn what they are and any differences between them.

Happy มีความสุข mee kwaam sùk

มีความสุข (mee kwaam sùk) is the direct equivalent of “to be happy” in Thai.

มี (mee) by itself means “to have” and ความสุข means “happiness”. So literally it means, to have happiness.

You use มีความสุข (mee kwaam sùk) to express that you are really super happy.

Examples:

• I am happy (females)
  ฉันมีความสุข
  chăn mee kwaam sùk
  
  
• I am happy (males)
  ผมมีความสุข
  pŏm mee kwaam sùk
  
  
• You make me happy
  คุณทำให้ฉันมีความสุข
  kun tam hâi chăn mee kwaam sùk
  
  
• Is she happy?
  เธอมีความสุขไหม
  ter mee kwaam sùk măi
  

Happy / Glad ดีใจ dee jai

ดีใจ (dee jai) is another way to say “to be happy” but less intense than มีความสุข (mee kwaam sùk). It is more equivalent to being glad.

You use ดีใจ (dee jai) to say you are happy in general or you are glad.

Examples:

• I am happy (females)
  ฉันดีใจ
  chăn dee jai
  
  
• I am happy (males)
  ผมดีใจ
  pŏm dee jai
  
  
• I am happy when I play with my dogs.
  ฉันดีใจเวลาเล่นกับสุนัข
  chăn dee jai way-laa lâyn gàp sù-nák
  
  
• She/he is glad she/he got to go.
  เขาดีใจที่เธอได้ไป
  kăo dee jai têe ter dâai bpai
  
  
• Is she/he happy?
  เขาดีใจไหม
  kăo dee jai măi

To understand the difference between มีความสุข (mee kwaam sùk) and ดีใจ (dee jai) think of the following situation.

Pretend you came back home from a long trip, your girlfriend would be really happy to see you so she can say มีความสุข (mee kwaam sùk). But your neighbor’s happiness is not really affected that much but he is still glad to see you and so he would use ดีใจ (dee jai).

Pleased, Happy ยินดี yin dee

Another word you might see that means happy is ยินดี (yin dee). However, ยินดี is mostly used when meeting someone and saying “I am happy to meet you” or “I am happy to welcome you”.

You don’t often use it to express general happiness.

Examples:

• I am happy to meet you
  ยินดีที่ได้รู้จัก
  yin dee têe dâai róo jàk
  
  
• Happy to welcome you
  ยินดีต้อนรับ
  dtôn ráp

---

To summarize – In general, to say you are happy in Thai you can use either มีความสุข mee kwaam sùk or ดีใจ dee jai (depending on the level of happiness).

To say you are happy to meet someone then use ยินดี (yin dee).