DOB Calculator: Find Your Date of Birth from Age (Plus Next Birthday & More)
1) What this DOB calculator does
Type your age in years, months, and days and the calculator returns your date of birth, the weekday you were born on, your zodiac sign, and a countdown to your next birthday. You can also switch to the “DOB → Details” tab to see your exact age from a known birth date. All math is calendar‑accurate—no rough “30‑day months”.
2) How DOB from age is calculated
We subtract the age components from the “as‑of” date in the order: years, months, then days. Months vary in length, so month subtraction snaps to the last valid day when needed—for example, subtracting one month from March 31 yields Feb 29 in a leap year or Feb 28 otherwise. This mirrors how official age is computed in HR and legal contexts.
3) Handling leap years and Feb 29 birthdays
If you were born on Feb 29, your birthday falls on Feb 29 in leap years. In non‑leap years, people often celebrate on Feb 28 or Mar 1; this tool defaults to Feb 28, with a toggle to use Mar 1 instead.
4) Next birthday and days remaining
The next birthday is the closest anniversary of your birth date on or after the as‑of date. We show the target date and how many days are left. If today is your birthday, the counter shows zero and “Happy Birthday!”.
5) Zodiac sign and weekday of birth
Your zodiac sign is determined by your month and day. We use the conventional Western date ranges. The weekday of birth is taken from your local calendar settings (e.g., Monday, Tuesday, etc.).
6) Step‑by‑step: use the tool
- Pick the mode: Age → DOB or DOB → Details.
- Set the as‑of date (defaults to today).
- Enter your age or date of birth and click Calculate.
- Copy the share link or download/print your results if needed.