Age is a stubborn fact: you can't hide or embellish it, but you can calculate it in different ways. Some rely only on the birth year and current year, others also consider the month and day, and the most meticulous even count seconds. Let's figure out how to correctly determine age and why results may slightly differ for different people.
At first glance, it's simple: subtract the birth year from the current year. But if someone was born in December and it's July, they haven't reached their full age yet. That’s why legal and medical documents always calculate age using the full date — day, month, and year.
Different countries have nuances. In Korea, for example, a child is considered one year old at birth. Therefore, it’s important to clarify the calculation method when working with international documents.
Nowadays, nobody calculates manually — just enter the date of birth in an online calculator. These tools show age in years, months, days, and even seconds. It's useful not only out of curiosity: accurate age is needed in law, sports, medicine, and retirement planning.
The algorithm is simple: the service takes the current date and compares it to the entered date. Depending on whether the birthday has passed this year, the result will be either the full age or one year less.
Why would you need to know your exact age? There are many reasons:
Sometimes age is just for curiosity — for example, to know how many days or seconds you have lived.
How to correctly calculate age by date of birth?
You need to consider not only the year but also the month and day. If the birthday has already passed this year, the age is counted as full; if not, one year is subtracted.
Why does age sometimes differ by one year?
This is because some count only years, while others also consider month and day. So in July, a person born in December may have "minus one year" until their birthday.
How to calculate age in months and days?
You need to subtract the birth date from the current date considering the calendar. The easiest way is to use an online calculator that shows age in years, months, days, and seconds.