A birthday is the one date that belongs to you every year. Still, many people cannot answer simple questions about it. How old am I in days? What weekday is my next birthday? How long do I have to wait?

The Birthday Calculator answers all of these questions. Enter your date of birth and it shows your exact age, the weekday you were born, your next birthday and a countdown.

For a simple age check, you can also use our Age Calculator.

A birthday calculator is an online tool that works with your date of birth. It does the calendar maths for you, so you do not need to count months or days by hand.

This calculator gives you:

• Your exact age in years, months and days.
• The weekday you were born.
• The date and weekday of your next birthday.
• The total days you have lived.
• A list of your next five birthdays with their weekdays.

The calculator subtracts your birth date from the chosen date in three steps:

• Years: subtract the birth year from the current year.
• Months: subtract the birth month from the current month.
• Days: subtract the birth day from the current day.

If the day or month result is negative, the tool borrows from the larger unit. A negative day count borrows the days of the previous month. A negative month count borrows 12 months from the years. Our guide on how to calculate age from date of birth shows the same method with worked examples.

Your next birthday is the first date on or after today with your birth month and day. The calculator also shows the weekday, so you can plan around work or school.

Your birthday weekday moves forward by one day each year. After a leap day it moves forward by two. This is why your birthday rarely lands on the same weekday two years in a row.

People born on 29 February have a real birthday only once every four years. In other years there are two common choices:

• Celebrate on 28 February.
• Celebrate on 1 March.

This calculator uses 1 March in non-leap years. Some legal systems use a different rule, so check the rule that applies to you. Read more about the leap year calendar.

• Individuals: to know their exact age or count down to their special day.
• Parents: to track a child’s age. See our Baby Age Calculator.
• Event planners: to pick a party date that suits the weekday.
• Students: to check age for forms and admissions.
• Families: to remember birthdays of relatives and friends.

Knowing the exact date and weekday makes planning easier.

• Check the weekday first. A weekday birthday may suit a small dinner, while a weekend birthday suits a larger party.
• Send invitations two to three weeks early.
• Set a simple budget before choosing a venue.
• Prepare a backup plan for outdoor events.
• Take photos, since each year is easy to forget.

Planning something for the future too? Try our Retirement Age Calculator.

• The result depends on the date of birth you enter.
• The tool counts whole calendar days and ignores birth time and time zones.
• It shows calendar dates, not legal rulings.
• Different cultures also count age in different ways, so the result may differ from a traditional age.

To compare any two dates, use our Years Between Dates Calculator.

Example 1: Regular Birthday

A person born on 15 August 2000 (a Tuesday) is 26 years, 1 month and 23 days old on 8 October 2026. The next birthday is Sunday, 15 August 2027, which is 311 days away.

Example 2: Leap Day Birthday

A person born on 29 February 2004 has no 29 February in 2027. The calculator shows Monday, 1 March 2027 as the next birthday, which is 144 days after 8 October 2026.

Example 3: Birthday Today

A person born on 8 October 1995 turns 31 on 8 October 2026, a Thursday. The calculator shows a birthday-today message.

A birthday is more than a date on a card. Knowing your exact age, your birthday weekday and the days left helps you plan and enjoy it more.

Enter your date of birth in the Birthday Calculator above. For more tools, visit agecalculator.net.pk.