Use this birthday calculator to find how many days are left until your next birthday, see your exact age, identify the birthday weekday and track upcoming age milestones. Enter only a month and day for a live birthday countdown, or add a birth year for detailed age results.
Birthday Calculator & Countdown
LiveYour birthday countdown
There is still time until your birthday.
Your day is on the way.
Upcoming age milestones
Saved birthdays on this device 0
Saved locally in this browser. Nothing is uploaded.
Private by design: birthday details are processed locally. A share link includes only the values needed to reproduce the countdown. Saved birthdays remain in this browser until you remove them.
What this birthday tool includes
Live countdown
Days, hours, minutes and seconds update without reloading.
Exact age
See completed years and a detailed calendar age when a birth year is entered.
Leap-day rules
Choose February 28, March 1 or the next true February 29.
Global time zones
Set the location where the birthday occurs and account for clock changes.
Calendar and sharing
Download an ICS event, copy a result, share a link or save a card.
Local birthday list
Save several birthdays on the device without creating an account.
How to use the birthday calculator
- Choose the birth month and day. These are the only required inputs to calculate the next birthday countdown.
- Add a birth year when you need age results. This unlocks current age, age on the next birthday and milestone years. For a separate date-to-date check, use the Age Calculator.
- Set the event details. Add an exact birthday time, target year, named time zone or February 29 rule. Use the Time Zone Converter when guests will join from different locations.
- Calculate and verify. Check the target date and time zone before copying the link, saving the image or adding the recurring event to a calendar.
How the birthday countdown is calculated
The tool builds the next valid birthday date in the selected time zone. If that date has already passed, it moves to the following year unless you entered a specific target year. The live timer then compares the current instant with the birthday instant, so daylight-saving changes are handled by the named time zone rather than by a fixed UTC offset.
Age is calculated from completed calendar years, not by dividing elapsed days by 365. For a February 29 birthday, you can use February 28, March 1 or the next actual leap day for the countdown. This setting changes the planning date only; legal age rules can vary by country.
Need a different answer? Use the Date Duration Calculator for elapsed years, months and days, or the Countdown Calculator for weddings, holidays, launches and other events.
Which birthday result do you need?
| Question | Required input | Result |
|---|---|---|
| How many days until my birthday? | Month and day | Live days, hours, minutes and seconds |
| How old am I today? | Month, day and birth year | Completed calendar age |
| How old will I be on my next birthday? | Full birth date | Age on the target birthday |
| What day of the week is my birthday? | Month, day and target year | Birthday weekday and full date |
| When does my birthday begin in another time zone? | Birthday time and named time zone | Exact event instant |
| When is my next milestone birthday? | Full birth date | Upcoming milestone ages and years |
Birthday calculation accuracy and limitations
Calendar age
The calculator uses Gregorian calendar dates and completed years. Historical calendars and jurisdiction-specific legal age rules can differ.
Time-zone changes
Named-zone calculations use the current IANA rules available in the visitor's browser. Governments can change future clock rules after a countdown is saved.
February 29 birthdays
The selected non-leap-year date is a planning preference. It should not be treated as a legal determination of when age changes.
Sources
These references document the date, time-zone and calendar-event standards used by the birthday calculator.
- RFC 3339 — Internet date and time representation.
- IANA Time Zone Database — named regional time zones and civil-time changes.
- RFC 5545 — the iCalendar format used by the downloadable birthday event.
- Numeros methodology — calculation, assumptions, testing and review principles.
Frequently asked questions
How many days are left until my birthday?
Choose your birth month and day. The birthday countdown calculator finds the next occurrence in the selected time zone and shows the remaining days, hours, minutes and seconds. The number of calendar days may differ from the total number of 24-hour periods when a daylight-saving change occurs.
Do I need to enter my birth year?
No. A month and day are enough to calculate your next birthday. Add the birth year only when you want your current age, age on that birthday, completed months and upcoming milestone ages.
How does the calculator handle a February 29 birthday?
For non-leap years, choose February 28, March 1 or wait for the next actual February 29. The option controls the countdown date; it does not determine the legal birthday rule in your country.
Does the birthday countdown account for time zones?
Yes. Select the location where the birthday occurs. The tool uses the named time-zone rules for the target date, including daylight-saving changes supported by the browser.
Are saved birthdays uploaded?
No. Saved entries use local browser storage on the current device and can be removed at any time.
Can I share the countdown or add it to my calendar?
Yes. You can copy the result, share a reproducible countdown link, save a birthday countdown image or download a yearly ICS calendar event. Verify the displayed date and time zone before sharing.
How old will I be on my next birthday?
Enter your birth year along with the month and day. The result panel shows your current completed age and the age you will reach on the calculated birthday.
Related calculators
See the full list of Date and Time calculators, or continue with:
- Age Calculator — find exact age between two dates.
- Countdown Calculator — create and share a live timer for any event.
- Date Duration Calculator — calculate elapsed years, months and days.
- Date Difference Calculator — compare two calendar dates.
- Add or Subtract Date Calculator — move a date by a chosen interval.
- Business Days Calculator — count working days before an event.
- Time Zone Converter — convert the celebration time globally.