Birthday Calculator
Find your next birthday, days remaining, age turning, and day of the week.
Your Next Birthday
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Days until birthday
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Age on next birthday
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Birthdate: —
Birthday Calculator Methodology
Enter your birth date and we’ll calculate your next birthday, countdown, age turning, and weekday.
Inputs
Process
We calculate your next birthday
Using exact calendar date logic
Results
Example birthday calculation
Date of birth
May 31, 1971
Today
May 28, 2026
ResultNext birthday + age turning
Calculator logic & edge cases
Birthday calculator FAQs: edge cases explained
Detailed answers about leap-day birthdays, days until your next birthday, date formats, time zones and other special cases.
How does the calculator decide whether my next birthday is this year or next year? Read full answerShow less
It places your birth month and day in the current year and compares that date with today. If it falls today or later, that is your next birthday. If it is even one day earlier than today, the calculator moves to the same date next year. For example, if your birthday was yesterday, the next one is usually 364 days away, or 365 when a leap day falls in between.
I was born on February 29. How does the calculator adjust for this, and why can it show February 28? Read full answerShow less
February 29 only exists in leap years, so in other years the calculator uses February 28 as your birthday and uses the real February 29 in leap years. For someone born on February 29, 2000 and checking on October 6, 2026, the next birthday is Sunday, February 28, 2027, 145 days away, and they turn 27. A note appears under the result whenever it shows February 28 for a leap-day birthday, and on February 28, 2027 the card shows "Today". Checking on March 1, 2027 jumps to the real February 29, 2028, which is 365 days away.
Why might another birthday calculator give a different result for someone born on February 29? This calculator uses February 28 in non-leap years, while some other tools use March 1 or wait for the next actual February 29. Read full answerShow less
There is no single universal rule for leap-day birthdays. This calculator uses February 28 in non-leap years. Some tools use March 1 instead, and others only count real February 29 dates, where the next one is usually four years later (and eight years across a non-leap century year such as 2100). Each choice is consistent, but they change the countdown by a day or more and can change the weekday shown. Laws and institutions also differ on when a leap-day birthday counts, so for legal or official age questions use the rule that applies to you. This calculator is meant for planning and countdowns.
Do the days until my next birthday include today? What if my birthday is today? No. Today is not counted; a birthday tomorrow is 1 day away, and a birthday today shows “Today”. Read full answerShow less
No. The calculator counts the calendar-day difference between today and your birthday, so a birthday tomorrow is 1 day away. A tool that counts both today and the birthday would show one more. If your birthday is today, the card shows "Today" instead of 365 or 366 days, together with the age you are turning today. If you were born today, that age is 0.
Why can the number of days until my birthday be different from one year to the next? A leap day can fall between today and your next birthday, making the calendar-day gap one day longer. Read full answerShow less
Years have 365 or 366 days, so the same birthday can be a different distance away depending on whether February 29 falls between today and the birthday. For a December 31 birthday checked on January 1, the countdown is 364 days in 2026 and 2027 but 365 days in 2028, because 2028 is a leap year.
Can daylight saving time or my time zone change the number of days until my birthday? Daylight saving time cannot change the day count, but your device’s local date determines what counts as “today”. Read full answerShow less
Daylight saving time cannot change it. The calculator compares calendar dates only, with no clock times, so a lost or gained hour has no effect. Your time zone only decides which date counts as "today": the calculator uses your device's local date. Someone in Auckland can be a calendar day ahead of someone in New York and see a countdown one day shorter for part of each day. The result is calculated when the page loads or you press Calculate birthday, so if you leave the page open past midnight, press Calculate birthday again (or reload) to refresh it.
How are the age I'll turn and the weekday of my next birthday worked out? The age comes from your next birthday year minus your birth year; the weekday comes from that next birthday date. Read full answerShow less
The age is the year of your next birthday minus your birth year. The weekday is the weekday of the calendar date of that next birthday, not the weekday you were born. For someone born May 31, 1971 and checking on October 6, 2026, the next birthday is Monday, May 31, 2027, and they turn 56.
What happens if I enter an invalid date such as February 30 or April 31? Impossible dates are rejected rather than auto-corrected, and the calculator requires a four-digit year. Read full answerShow less
The calculator rejects it with a message, hides any earlier result so an old answer is not mistaken for a new one, and never auto-corrects the date (February 30 is not turned into March 1 or 2). It checks that the month is 1 to 12, that the day exists in that month for that year, and that the year has four digits. Because February 29 only exists in leap years, the year matters: 29/02/2000 is accepted, and 29/02/1900 is rejected because 1900 was not a leap year. A two-digit year such as 85 is not guessed at, so enter 1985.
Can I enter a future birthdate? No. A birthdate must be today or in the past; future dates are rejected. Read full answerShow less
No. The calculator shows "Enter a birthdate that is today or in the past" because it needs a birth date that has already happened to work out your next birthday and the age you will turn. Today's date is accepted. If a future date arrives from another tool on this site, it stays in the boxes with the same message. To find the gap between any two dates, including future ones, use the age difference calculator.
Can I use a birth year before 1900? Yes. Past dates from year 0001 onward are supported when all four year digits are entered. Read full answerShow less
Yes. Any past date from year 0001 onward is accepted, as long as you type all four digits (for example 0042), and there is no age limit, so 1850 shows "Turning 177". The calculator does not judge whether a date is realistic. Historical dates use the proleptic Gregorian calendar, which applies today's leap-year rules backward and ignores the Julian calendar and the 1582 reform. This matters only for leap days: February 29, 1500 is rejected because 1500 is not a Gregorian leap year, even though the Julian calendar then in use had one. For research that depends on the calendar in use at the time, convert the date first.
What happens if I switch between DD/MM/YYYY and MM/DD/YYYY after I start typing? The day and month boxes swap so the date you typed stays the same, and your format choice is remembered for the browser session. Read full answerShow less
The boxes swap so the date you typed stays the same: 15/06/1990 becomes 06/15/1990, and half-finished entries swap boxes too. Switching never changes which date is calculated: the result keeps showing the last date you calculated, re-written in the new format (for example Monday, 31 May 2027 versus Monday, May 31, 2027), until you press Calculate birthday. Your format choice is remembered for the browser session. When you paste a date, the active format decides which number is the day and which is the month, so 05/06/1990 is June 5 in DD/MM/YYYY and May 6 in MM/DD/YYYY. Dates written year first (such as 1990-05-31) and 8-digit dates are also recognized.
Why is my birthdate sometimes already filled in when I open the calculator? A date can be carried from another age tool or remembered for the current browser session; otherwise the page shows an unsaved example date. Read full answerShow less
Three situations can fill it in before you type. If you arrived from another tool on this site, the date is carried over and a badge usually says where it came from (a link someone shared with you also fills it in, without a badge). If you calculated a birthdate earlier on the Age Calculator or here, it is remembered only for the current browser session, the badge reads "Saved birthdate from this session", and it is forgotten when you close the tab or window. If neither applies, the calculator shows an example date, May 31, 1971, which is not remembered. Editing any box removes the badge.
Does copying or sharing my result include my birthdate? Yes. Copy summary and Share results include your date of birth, so use the browser address if you want to share the calculator without it. Read full answerShow less
Yes. Copy summary puts your date of birth in the copied text. Share results includes it too: on devices with a built-in share menu it sends the summary and a link, otherwise it copies a link that carries your date in the web address, so anyone who opens that link sees it. The links to other tools on this site also pass the date in their address so the next page can fill it in. To share the calculator without your date, copy the page address from your browser's address bar instead of using Share results.