Birthday Calculator

The birthday calculator will accurately answer the question, "When is my birthday?" It can also serve as an age calculator, allowing you to calculate your age in seconds, minutes, hours, days, weeks, months, and years.

This tool can also serve as a date of birth calculator (in case you know exactly how many days old you are) or the dates of your past birthdays (in case you're wondering, e.g., "when was my 14th birthday?").

Fun fact: There's a 50% chance that at least two people in a group of 23 share a birthday. To learn more about this, visit our Birthday Paradox Calculator.

Keep reading to learn:

• How to use the birthday calculator;
• How to find the dates of your past or future birthdays;
• The ancient roots of birthday traditions; and
• More.

If you're wondering, "When is my birthday?" you're just a few clicks away from the answer:

1. In the first field of the birthday calculator, click the calendar icon and choose your date of birth. You can also type it in (the first three letters of the month followed by the day, and the year, e.g., "Sep 25, 1980").

2. In the second field, you can set the date for which you want to calculate your age and the time left until your next birthday. By default it is set to today. To include the time in the calculations, check the Count hours and minutes box.

3. Based on these two dates, the birthday calculator will estimate your age and display it in the third field. You can choose between different units of time to find out how many seconds, days, weeks, etc., you have lived.

4. Under the birthday calculator, you'll see the time left until your next birthday.

5. You can also use our tool to determine your age at a specific event in the past or your age at a given date in the future.

Are you interested in learning how many months there are between two dates? Visit our intuitive month calculator.

Our tools enable calculations in different directions. This feature lets you answer a wider variety of questions.

Let's see what questions this birthday calculator/date of birth calculator can answer and how to go about it.

When was I born?

You could use our birthday calculator as a date-of-birth calculator, but you'd have to know your exact age. So, if it's your birthday and you know you're 85 but forgot your date of birth, here is what you do:

1. Enter your age in the third field of the calculator.
2. Set the second field to today's date.
3. In the first field, you should now be able to see your date of birth.

When was my 14th birthday?

Let's say you wish to figure out how long ago something happened. All you are sure about is that it happened on your 14th birthday. So now you are asking yourself, When was my 14th birthday?.

Calculate your 14th birthday quickly and easily by following these steps:

1. Enter 14 in the age field.
2. Add your date of birth in the date of birth field.

You should now be able to see the date of your 14th birthday in the second field of the birthday calculator.

When was I 10,000 days old?

Calculating the date you were or will be 10,000 years old is pretty easy with our date of birth calculator. Here is what you need to do:

1. Set your date of birth in the first field.
2. Change the unit in the last field to "days" and enter "10,000".
3. In the On... field, you'll see the day you were or will be 10,000 days old.

When will I be 100 years old?

Follow these steps to figure out the day on which you will be 100 years old:

1. In the field labelled age, change the unit to years.
2. Now in the same field, enter 100.
3. Enter your date of birth in the first field.

You can now see the date you will be 100 years old in the ** On... ** field.

How long would I have to live to see the first day of the 22nd century?

To figure out how long you would need to live to see the first day of the 22nd century, follow these steps:

1. Set your birthdate in the first field.
2. Type Jan 1, 2101 in the second field.
3. Your projected age will be displayed in the last field of the birthday calculator.

You can use our birthday calculator to find the number of days until a given event. Suppose you want to know the days between February 01, 2025, and March 04, 2025.

1. Click on the calender icon in the first field of the birthday calculator labelled date of birth.
2. Scroll on the calendar until you find February 2025.
3. Click the first day of February.
4. In the second date section, click on the calendar icon to choose March 04, 2025.
5. In the last section labelled age, change the unit to days.
6. You should now be able to see the number of days in the age section.

That's it! You just used Omni's birthday calculator to find the number of days until a particular event.

Are you interested in learning to manually calculate your friend's date of birth based on their present birthday? Follow these steps:

1. Suppose Bob's birthday is on April 21, 2025, and he is 36 years old.
2. To find his date of birth, you need to subtract 36 from 2025, which gives you April 21, 1989.

To save time, use our birthday calculator to explore examples more complicated than this one.

Have you ever wondered "How we developed the custom of blowing candles out on our birthdays?"

The history of celebrating birthdays is strictly connected to the invention of the calendar. Before it, there was no way to mark and conceptualize birthdates.

There are different ways to determine your age, depending on the calendar that you are considering. For instance, in the Hijri lunar calendar, you must multiply your age (in the Gregorian calendar) by the factor 0.027 and then add the result to your age. Besides, in the Chinese calendar, you need to consider one extra year for your time of birth and another one if the Chinese New Year has already happened. Therefore, someone 40 years old in the Gregorian calendar will be 41 years old in the Hijri calendar and 42 years old in the Chinese calendar (considering that the Chinese New Year has passed).

In the beginning, birthdays were thought to be dangerous, and we're not talking about the amount of alcohol consumed. The ancient pagan cultures believed that evil spirits visited the man on his birthday. For this reason, a community would gather to protect him and wish him well. People would dance and sing loud to scare the demons away.

Ancient Romans' birthdays were also connected with a spirit, although not a malicious one. The being was a guardian spirit called "genius." It accompanied a man throughout his life since birth and protected him. A birthday would be a ceremony to honor one's genius. Romans would sacrifice a bread cake and some wine for the spirit. On a paterfamilias (landowners') birthday, relatives also lit candles, expressed wishes, and gave blessings.

And what about the cake? We know that the ancient Greeks took a round cake with candles to the Temples of Artemis - the moon goddess. They believed that lighting candles enabled connection with gods.

Source: Redlich, O. (2020). The Concept of Birthday: A Theoretical, Historical, and Social Overview, in Judaism and Other Cultures.