Admittedly, this is one of the more difficult things I ever had the pleasure of coming to understand - BUT once you get it, it’s actually pretty simple! It will require a bit of concentration if this kind of aging system is something you are unfamiliar with though. 

To start off, most fans of Hallyu know that Koreans (and a whole bunch of other ethnic groups too by the way) age a little bit differently than the rest of us do. So, how do you work out how old you would be considered to be in Korea? 

According to Wikipedia, “East Asian age reckoning (which is this aging system you are trying to figure out) is a concept and practice that originated in China and is widely used by other cultures in East Asia.” You can read up some more about it by following that link if you’d be interested. The general idea though is that when a baby is born, it is already a year old. 

The next thing you need to know is that in Korea, a person does not age on their birthday - that happens at the start of the new year. This means that a baby born on December 30th can be considered to be 2 years old on January 7th of the following year even though it was born only a few days ago!

The tricky part about this aging system is figuring out if you’re 1 or 2 years older than your Western age. This is where it gets a little complicated, and confuses the bajeebers out of people. You will need to take the Lunar New Year into consideration when trying to figure out your Korean age. 

We know that politeness in speech is a very big part of the culture and that it does more than just show you have good manners. A person’s age is one of the things used in determining which speech levels to use when interacting with people. 

As you learnt earlier, all babies are born aged 1 years old, and they will gain another year at the start of a new year. BUT, the trick to this is figuring out WHICH year the baby is considered to be a part of! This is where the Lunar Calendar comes in~ Yes, this does matter - a lot actually.

Let’s take Jhope’s birthday to try to make this easier to understand.

Hobie was born: February 19, 1994.
The lunar year for that year was 10 Feb 1994 - 30 Jan 1995. Hobie was born AFTER the Lunar New Year had already occurred. This means that he only ages again at the start of the next Lunar New Year. 
This makes Hobie 23 years old (in 2017) by the Western aging system, but 24 years old by the Korean one.

INFINITE’s Woohyun however, was born February 8, 1991. 
The lunar cycle for 1991-1992 was for the period of 15 Feb 1991 - 3 Feb 1992. 
Woohyun was born BEFORE the new year started. This changes how he is aged because his birthday falls under the lunar cycle of the year before he was born - 1990-1991. This means that Woohyun is aged a second time because the start of the lunar new year for the year he is born in happened after he was born; and therefore makes him 2 years old when he was technically only a few days old. 
He is 26 by the Western aging system, and 28 by the Korean one. 

This is why he is considered to be friends (meaning: the same age) with Dongwoo (November 11, 1990) but Hoya (March 28, 1991) and Sungyeol (August 27, 1991) are both considered to be a year younger than him even though Woohyun and Hoya are born a month and a half apart. 

It is also why Sunggyu (who is almost 28 years old by Western standards) is only considered to be a year older (29) than Woohyun even though there are literally 2 years separating them. 

Still confused? Maybe this will help: 

Woohyun’s birthday is included in the 1990-1991 lunar year cycle, so he gets a second year added. Hoya and Sungyeol were both born during the 1991-1992 lunar year cycle, so they are both a year younger than Woohyun. 

Let’s work out an age to see if you understand how it works. Don’t cheat! Try to work it out by yourself. 

16 February 1988. What age do you get?

His Western age is 29 and his Korean age is 31. Why? 
Lunar year 1987-1988 =  29 Jan 1987—16 Feb 1988 Year of the Rabbit
Lunar year 1988-1989 =  17 Feb 1988—5 Feb 1989 Year of the Dragon
* 1 years old at birth +
* 29 years old literal age = 30 years old +
* As you can see, Kim Soohyun’s birthday makes him a Rabbit, so he is considered to be a part of the previous year. He therefore gets 2 years added to his literal age. 

Shall we try another one? 

30 October 1981

The answer: Jeon Jihyun’s Western age is 35 and her Korean age is 36.
Here’s why: 
Lunar year 1981-1982 =  5 Feb 1981—24 Jan 1982 Year of the Rooster
* 1 year at birth +
* 35 years old literal age = 36 years old. 
* Her birthday makes her a Rooster and because it is after the lunar new year for the year she was born in had occurred, she does not get a second year added to her literal age. 

An easy tip I can give you is that if your birthday is in the range from Late February to Mid January of the following year, chances are that you will only get 1 year added to your age because your birthday will almost always be after the Lunar New Year for the year you were born in has already occurred. 

Typically, the Lunar New Year takes place between January and February and though it has happened that it’s been earlier or later, these were EXTREMELY rare cases.** It is most likely that only people born during the first two months of a Gregorian calendar year may require 2 years to be added to their literal age instead of just 1 year. (**recently learnt that the Lunar New Year is set between January 21st & February 20th - thanks for the info, fantasylovemusic ) 

You should also keep in mind that you are aged at the beginning of the year, and not your birthday. (The exception to this is the Coming of Age day, but that is a whole other story and honestly won’t impact your Korean age too drastically.) So, someone born in December is seen as being the age they would be at their birthday, for that full year. 

For example:

December  5 1995 = born = 1 years old
January 1 1996 = New Years = 2 years old (even though at this date the baby was born only a month ago. 
December 5 1996 - Birthday = still 2 years old
January 1 1997 = New Years = 3 years old

And that’s how to figure out what your Korean age is. 

1. The year you were born having.
2. Your literal age.
3. Which lunar year cycle your birthday falls under. If it includes the previous year then + 1 year.

Here is a link to a long list of Lunar New Year dates so you can have fun working out the Korean ages of all your family and friends. Hope this was helpful~ 

So, what is YOUR Korean age? =D