Calculate age from date of birth
 What is age?
 Knowing your date of birth
 How to calculate age from date of birth on your own?
 Example of calculating age from date of birth
 Calculate age from date of birth with online calculator
 Example of use of online calculator
 Comparison of calculating age from date of birth
 The summary of calculating age from date of birth
Calculating age is one of the most commonly done calculations. And that’s totally understandable, because knowing our age is so important in everyday life. But sometimes just age in years is not sufficient. Sometimes it is necessary to know the exact age and calculate age from date of birth. And that’s the main topic of this article.
So if you want to know how to calculate age from date of birth in two different ways, it means by doing your own calculations and using a dedicated tool, and finally know your exact age, you are in the perfect place. So let’s start the article!
What is age?
First things first. Do you know what age is? How do you define this term? Age is mostly defined as the time in which you are alive. It is usually measured in years only. But age given in years is not exact. There are also months and days, after all.
That’s why to know your exact age, you need to calculate age from date of birth, not the year of birth only. Of course, the obtained result won’t be so exact to know how old you are in seconds, but will be sufficient to say you know your exact age.
All the things we said in this part concern only normal age. Why do we emphasize that? It is needed to remember that there are also other kinds of age other than chronological age, for instance, Korean age, which is calculated differently.
So to sum up, the age is the difference which you will get after calculating age from two dates, in this case date of your birth and the current date, not only year of your birth and current year.
Knowing your date of birth
There is one thing without which there is no way to calculate your exact age. Maybe you now imagine what we are talking about. This is your date of birth, of course! How to calculate age from date of birth without knowing date of birth? It is impossible. So before we start the calculations, please remember your date of birth.
Most of us just know when we were born. But if you forget or have some doubts, you can ask your parents, check your birth certificate to get the exact date. Remember that only when you know your exact date of birth, you will get the exact result of your age.
Have a look at these two situations. Obviously there is a difference between when you were born on 31 December 1998 and 1 January 1999, don’t you think? That’s why even only one small day matters in this case.
How to calculate age from date of birth on your own?
Calculating age from date of birth is just calculating age from two dates. It means, you need to know your date of birth and the current date. Then you will be able to make calculations and know the difference between them. To make your calculations as easy as possible, we are going to show you how to calculate age from date of birth on your own in 3 steps.
The first step is to calculate how old you are in years. It means, we are going to calculate only the full years you are alive. For instance, you were born on 25 May 1998. So now you need to check if your birthday has passed this year. And let’s suppose that now is 26 November 2021. So yeah, your birthday has passed this year. It means you can calculate the years between your year of birth and the current year. Remember – if your birthday hasn’t passed this year, calculate the full years between your year of birth and the previous year, not current.
The second step is to calculate months which are left after calculating full years. It means, we are going to calculate how many months are between May and November. But be careful here too and check only full months. It means, when the day in which you were born has passed this month, calculate from the month of your birth to the current month. If not, calculate only from the month of your birth to the previous month.
The third step is to calculate days which are left after calculating full years and full months. It means, we are going to calculate how many days are between 25 and 26. In this example, the calculations will be quite easy. But remember, the number of days which are left won't ever be bigger than 30.
Example of calculating age from date of birth
So if you know how to calculate age from date of birth in theory, it’s time for practice. We are going to make it in 3 steps, as we show you in the theoretical part. So if you need a reminder, you can check the theory above.
A quick reminder of data:
Your birthdate: 25 May 1998
The current date: 26 November 2021
The first step – calculating full years from date of birth.
The calculations will look as follows:
2021  1998 = 23
The second step – calculating full months from date of birth.
May is the 5th month of the year, November is the 11th month of the year, so the calculations will look like this:
11  5 = 6
The third step – calculating days which are left after calculating full years and full months from date of birth.
Have a look at the calculations:
26  25 = 1
So now it’s time to sum up the results and gather them in just one result. Have a look at the answer:
If you were born on 25 May 1998, and now it is 26 November 2021, you are 23 years 6 months and 1 day old.
We hope that after seeing this example, calculating age from date of birth is quite simple for you.
Now it is time to see another way to know your exact age – so much easier and without any calculations on your own. Do you want to see what we are talking about? Check the next part of the article.
Calculate age from date of birth with online calculator
We know that showing the example above, even in 3 simple steps, can not be sufficient. Some of you just don’t like calculating on your own, some of you are looking for a tool which will make everything for you. And that’s okay. We understand it. That’s why we created the online calculator, a kind of what is my age now calculator.
The online calculator is created to calculate age from date of birth without any effort. You don’t need to make any calculations on your own. They will be made by our app, and you will be able to enjoy the result in less than a second.
The online calculator is entirely based on the Internet. It means to use it you need only a device with Internet connection. That’s all. The use of this tool is free, so you don’t have to worry about paying any charges.
How to use the online calculator to calculate age from date of birth? There is nothing complicated, you will see. First, you need to enter your date of birth, it means day, month and year. You need to enter the current date, it is updated automatically. Then click the ‘calculate’ button down below and see the result. Easy? As it’s like!
Example of use of online calculator
After theory, it’s always time for practice. So in this part, we will show you how to use the online calculator to calculate age from date of birth. We know that if something is divided into steps it looks simpler, so in this way we will show you an example of usage of the online calculator.
As in the previous example of calculating age from date of birth on your own, we need some data. So we will use the same one. A quick reminder is down below.
Your birthdate: 25 May 1998
The current date: 26 November 2021
And now we can start the example!

First step – enter your date of birth, in this case 25 May 1998.

Second step – check if the current date is okay. Today it is 26 November 2021.

Click the ‘calculate’ button down below.
That’s all! Enjoy your result obtained in an easy, quick and free way!
So you are 23 years 6 months and 1 day old if you were born on 25 May 1998, and today it is 26 November 2021.
We are pretty sure that now you can use our online calculator to calculate age from date of birth without any trouble.
Okay, some of you can say it is possible to calculate age in Excel from birthday too. But have a look at the example again. If you have a readymade solution, as simple to use, why to use an Excel to make this calculation?
Comparison of calculating age from date of birth
You know two different ways to calculate age from date of birth. First is calculating by yourself, second is calculating using an online calculator. At the end, we prepared a little comparison of these methods. Thanks to it, you will be able to choose the best one for you.
Calculating age from date of birth by yourself is a method which can be useful, especially in school, when teachers prefer that their students make everything on their own. It is also a good method for those of you who just like calculating. You can use this way, for instance, to make some competition with your friends. And last but not least – it's the perfect method when you have no access to the Internet and don't have a physical calculator by your side.
Calculating age from date of birth using the online calculator is a much quicker, simpler and effortless way to get the result. It is the best way for those of you who don’t like calculating on your own. It is also a good choice for those who like technological innovations and readymade solutions. Probably it will be the choice of most of you when you don’t have to make calculations by yourself for some cases.
The summary of calculating age from date of birth
That’s all we have for you in this article. We hope that now calculating age from date of birth has no secrets behind you. So it’s time to use this knowledge in practice. Remember your date of birth and check your exact age – by yourself or using our online calculator.
Check also our other article about age. We have plenty of them. Just pick these ones which interest you the most. We promise, after reading them you will be able to surprise your math teacher, friends and family!