About the Age Calculator
The Age Calculator works out an exact age from a date of birth: whole years, plus the months and days since the last birthday. It also shows when the next birthday is, which weekday the person was born on, the age in total months, weeks, days and hours, and the star sign.
By default it calculates the age today, but you can pick any other date. That answers questions like "How old will I be on my wedding day?", "Was this applicant 18 on the closing date?" or "How old was my grandfather when he emigrated?".
The math follows the calendar, including leap years and months of different lengths, and the examples below show exactly how the tricky cases are handled. Everything runs in your browser, and the dates you enter are not stored or sent anywhere.
How to use it
- Enter the date of birthType or pick the date in the "Date of birth" field.
- Choose the date to measure to"Age on this date" starts with today's date. Change it to any past or future date, or click Use today to go back.
- Read the ageThe result shows the age in whole years, with the full years, months and days underneath.
- Check the detailsThe list shows the next birthday and its weekday, the weekday of birth, the totals in months, weeks, days and hours, and the star sign.
- Copy the resultCopy result puts a one-line summary on your clipboard, with both dates written out.
Key features
Exact calendar age
Years, months and days counted the way people count birthdays, not by dividing days by 365.
Any reference date
Calculate the age today, on a date in the past or on a date in the future.
Leap years and month ends
February 29 birthdays and birthdays on the 29th, 30th or 31st are handled by clear, consistent rules.
Next birthday
How many days are left, and the weekday and date of the next birthday.
Totals
Age in total months, in weeks and days, in days and in hours.
Private by design
No account and no upload. The dates stay in your browser.
Examples
A regular birthday
Date of birth May 15, 1990, age on October 10, 2026:
| Result | Value |
|---|---|
| Age | 36 years, 4 months, 25 days |
| Next birthday | In 217 days, Saturday, May 15, 2027 |
| Born on a | Tuesday |
| Total months | 436 |
| Total weeks | 1,899 weeks, 4 days |
| Total days | 13,297 |
| Total hours | 319,128 |
| Star sign | Taurus |
The total days include the 9 leap days between those dates (from 1992 to 2024): 36 × 365 + 9 = 13,149 days to the 36th birthday, plus 148 days from May 15 to October 10.
Born on February 29
Someone born on February 29, 2000 only has a real birthday in leap years. In other years, the tool uses February 28:
| Age on | Age | Next birthday |
|---|---|---|
| Feb 28, 2025 | 25 years | Today. Happy birthday! |
| Mar 1, 2025 | 25 years, 1 day | In 364 days, Saturday, February 28, 2026 |
| Feb 28, 2028 | 27 years, 11 months, 30 days | In 1 day, Tuesday, February 29, 2028 |
| Feb 29, 2028 | 28 years | Today. Happy birthday! |
Legal rules differ: some countries and agencies count a leap-day birthday on March 1 in common years. Check the rule that applies if the exact day matters, for example for a driver's license or a pension.
Birthdays at the end of a month
Born January 31, 2010, age on March 1, 2026: 16 years, 1 month, 1 day. There is no February 31, so the one-month mark falls on the last day of February (February 28, 2026), and March 1 is one day later. In a leap year the one-month mark would be February 29.
Star sign cut-offs
The tool uses the usual newspaper table. Born January 19 gives Capricorn, January 20 gives Aquarius; August 23 gives Virgo. The real changeover moves by a day in some years, so people born on the first or last day of a sign may see a different sign elsewhere.
Tips
- To check an age requirement, set "Age on this date" to the deadline, not to today. "18 years" or more means the person had turned 18 by that day.
- Planning a party or a milestone? Set the date to the event to see the exact age, or use the Days Until Calculator for a live countdown to the birthday.
- For the time between two dates that are not birthdays, such as a contract or a project, the Date Difference Calculator also counts weekdays.
- The "Born on a" row is a quick way to find the weekday of any historical date: enter it as a date of birth.
- Copy result writes both dates out in full, which avoids confusion between month-first and day-first date formats in emails.
Common mistakes and limits
- Dividing days by 365 to get yearsThat ignores leap years and drifts by about a day every four years. The tool counts calendar years from the birthday instead.
- Reading "Total hours" as exactIt is the total days times 24, counted from midnight to midnight. It does not know the time of birth and does not adjust for daylight saving time.
- Mixing up time zones near midnightThe default date is today on your device. Someone in another time zone can already be a day ahead or behind, so pick the date yourself when that matters.
- Assuming a leap-day birthday is always February 28The tool uses February 28 in common years, but some laws use March 1. Use the rule that applies to your situation.
- Typing the date in the wrong orderDate fields follow your browser's format, which may be day-first on some devices. Check the full date in the copied summary if in doubt.