Birthday Calculator
Enter your birth date to discover your age on a given day, how many days remain until your next birthday, and the celebration weekday.
Defaults to today. Pick any date to plan future birthdays.
Birthday Snapshot
As of November 25, 2025
Age: 30 year(s)
Last birthday: July 14, 2025
Next celebration
Birthday #31 on July 14, 2026
Falls on Tuesday • 231 day(s) away
How to Use This Calculator
Enter your birth date
Use the exact day you were born. The calculator handles leap year birthdays by rolling non-leap celebrations to Feb 28.
Set a reference date
Choose today to get a live countdown, or enter a future date to see how old you will be on trips, events, or milestones.
Read the results
See the age today, when your next birthday occurs, the day of the week, and how many days remain.
Formula
Age = Reference Year − Birth Year (subtract 1 if birthday not reached)
Next Birthday = Birth Date with current year (or +1 if already passed)
Days Until = ceil((Next Birthday − Reference) ÷ 86,400,000 ms)
Example: Born 1995-07-14, today 2025-11-09 → age 30, next birthday #31 on Monday, July 14, 2026, 248 days away.
Birthday Planning Tips
Countdown knowledge helps you plan gifts, vacations, and parties in advance—especially when birthdays fall on busy weekdays.
- Send save-the-date reminders 30 days out if your birthday falls on a weekend.
- Sync the countdown with travel planners for destination birthdays.
- Use the age-on-date feature to plan age-specific milestones (licenses, retirements, etc.).
- Track multiple birthdays by saving personalized calculator inputs for friends and family.
Frequently Asked Questions
What about leap-year birthdays?
Non-leap years default to celebrating on February 28. The calculator adjusts automatically.
Can I use this for someone else?
Yes—enter anyone’s birth date to plan surprises or send thoughtful reminders.
Does time zone affect the result?
No. Calculations are based on calendar days. If births around midnight matter, adjust the reference date manually.
Can I export the countdown?
Copy the results into a calendar app or reminder tool to keep birthday notifications handy.