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Time, Date & Personal Calculator
Birthday Calculator
Calculate age, next birthday, days until birthday, weekday born, total days lived and zodiac sign from a birth date.
Age and next birthday calculator
Age–
Next birthday–
Days until birthday–
Zodiac sign–
Enter a birth date to calculate birthday details.
Birthday calculations included
- Current age in years, months and days.
- Days until the next birthday.
- Total days lived as of the selected date.
- Weekday of birth and weekday of the next birthday.
- Western zodiac sign from the birth month and day.
Age calculation note
Age = completed calendar years + remaining calendar months + remaining days
Calendar ages are not the same as dividing total days by 365 because months and leap years vary.
Birthday Calculator FAQ
How is age calculated?
The calculator counts completed calendar years, then months and days up to the selected target date.
Does it handle leap years?
Yes. JavaScript date handling accounts for leap years when calculating real calendar dates.
What if my birthday is today?
The days until birthday result shows 0, and the next birthday shown is today.
Is the zodiac sign included?
Yes. The calculator shows a common Western zodiac sign based on month and day.
Can I calculate age for a past date?
Yes. Set the calculate-as-of date to any date after the birth date.
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