If you have Korean friends or acquaintances or if you are/will be spending a decent amount of time in Korea, this will be a handy phrase to know.
You will eventually want to congratulate someone on a graduation, a birthday, wedding, etc. Notice that there are four ways to say congratulations.
*side note: don’t use Google Translate for this as it will turn out something completely different and you will sound weird*
Congratulations in Korean Casual/Informal
For the casual/informal form, you will simply say 축하해!. Notice that the ‘요’ is dropped as usual for the casual form. You would say this to very close friends, children, and someone younger than you (if you’ve had their permission to use the casual form). This is especially used on birthdays.
Congratulations in Standard Polite Informal
The second one is 축하해요! The 요 has been added on and you would say this to acquaintances, not so close friends, coworkers, and neighbors. However you can use the next form as well if it’s a formal occasion.
Congratulations in Formal
In the formal form, you would use 축하합니다! Use this with people older than you. You would also use this to congratulate someone on their wedding or graduation.
Congratulation in Very Formal
For the very formal form, you would use 축하드립니다! Use this with bosses, teachers, or in general people with positions of power over you in the workplace.
There are some variations with these. For example for weddings, you can use 축하드려요 which is a more casual form of 축하드립니다 while still being formal. For example 결혼 축하드려요! (결혼 = wedding). You can just add the occasion to the beginning of your congratulations. For close friends, you can simply use the Polite informal form for most situations.
결혼 = Wedding
졸업 = Graduation
생일 = Birthday