⏱TimeCalcLab

Age Calculator

Calculate exact age in years, months and days from a date of birth, or the time between any two dates. Enter a date of birth and optionally a date to calculate age on (it defaults to today), then read the years, months and days breakdown plus total months, total weeks and total days. Everything updates instantly and runs in your browser.

Your age

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Enter a date of birth to see the result.

Example: Date of birth June 15, 1990, age on August 20, 2026 = 36 years, 2 months, 5 days (434 months, 13,215 days).

How to Use an Age Calculator

  1. Enter your date of birth.
  2. Optionally enter a date to calculate age on — leave it blank to use today.
  3. Read your age in years, months and days, plus total months, total weeks and total days.

How Age Is Calculated

Age is the calendar difference between your date of birth and the target date. The calculator subtracts years first, then months, then days. When the target day is earlier than the birth day, it borrows days from the previous month (using that month's real length). When the target month is earlier than the birth month, it borrows months from the previous year. This is true calendar arithmetic — it never divides total days by 365 or by 30, so the result is exact even across February and leap years.

Age in Years, Months and Days

The primary result expresses age the way people normally speak: a count of completed years, then completed months within the current year, then the remaining days. For example, someone born on June 15, 1990 is 36 years, 2 months and 5 days old on August 20, 2026. The months and days are not a fraction of a year — they are real calendar months and days, so the breakdown is always consistent with the calendar.

Age in Total Days

The total-days figure counts every whole calendar day that has elapsed between the date of birth and the age-on date, using UTC so daylight saving never shifts the count. The same span is also shown as total weeks (total days ÷ 7, rounded down) and total months (years × 12 plus remaining months). For the June 15, 1990 to August 20, 2026 example that is 13,215 days, 1,887 weeks and 434 months.

Leap Years and Birthdays

Leap years add an extra day, February 29, which affects the total-days and total-weeks counts but not the years-months-days breakdown. If you were born on February 29, the years-months-days result treats your birthday as the last day of February in non-leap years, while the total-days count still reflects the true elapsed days. A year is a leap year if it is divisible by 4, except century years which must be divisible by 400.

Age Calculator vs Date Difference Calculator

This Age Calculator is tuned for people: it starts from a date of birth, defaults the second date to today, and reports age in years, months and days. The Days Between Dates Calculator measures the gap between any two dates as total days, weeks and a calendar difference, while the Date Add & Subtract Calculator starts from one date and moves forward or backward by a duration to find a target date.

Common Age Calculation Mistakes

  • Dividing total days by 365. That gives an approximate age in years and ignores leap years; the exact method uses real calendar months.
  • Assuming every month has 30 days. Real months range from 28 to 31 days, so a 30-day month drifts the days figure.
  • Forgetting the birthday has not happened yet. If the target date is before the birthday in the current year, the years figure is one less and months borrow from the year.
  • Counting the birth day as a lived day. Age counts elapsed days after birth, so the day someone is born is day 0, not day 1.
  • Timezone and DST errors. This calculator treats inputs as calendar dates and counts in UTC, so daylight saving never changes a whole-day result.

FAQs

How do I calculate my exact age?
Enter your date of birth and the date you want to calculate your age on (it defaults to today). The calculator works out the difference using real calendar months and leap years, so the result is shown as years, months and days — for example, 36 years, 2 months, 5 days. It also shows the same span as total months, total weeks and total days.
How many days old am I?
Enter your date of birth and leave the age-on date blank to use today. The "Total days" figure is the number of whole calendar days that have elapsed since you were born, counted in UTC so daylight saving never changes it. For example, someone born on June 15, 1990 is 13,215 days old on August 20, 2026.
How is age calculated?
Age is the calendar difference between your date of birth and the target date. The calculator subtracts years, then months, then days, borrowing from the previous month when the target day is earlier than the birth day, and from the previous year when the target month is earlier than the birth month. This uses true calendar arithmetic rather than dividing total days by 365 or 30.
Do leap years affect age?
Yes, but only the total-days and total-weeks figures change, not the years-months-days result. A leap year adds an extra day (February 29), so the total number of days elapsed between two dates depends on how many leap years fall in between. The years, months and days result is unaffected because it is built from real calendar months, which already include February 29.
Can I calculate age on a future date?
You can calculate age on any date you enter in the "Calculate age on" field, including a future date — the calculator will show how old someone will be on that date. However, a date of birth that is in the future relative to the age-on date is rejected, because a person cannot yet have been born.
How many months old am I?
Enter your date of birth and leave the age-on date blank to use today. The "Total months" figure is the number of whole calendar months elapsed since your birth — that is, years × 12 plus the remaining months. For example, someone born on June 15, 1990 is 434 months old on August 20, 2026 (36 × 12 + 2).
What happens if my birthday has not happened yet this year?
The calculator handles this automatically. If the target date is before your birthday in the current year, the years figure is one less and the months figure borrows from the year. For example, born May 20 and checking on March 10 of a later year gives a result ending in "10 months, 18 days" rather than a full year.
Does the calculator work for leap-day birthdays (February 29)?
Yes. If you were born on February 29, the calculator uses real calendar dates. In a non-leap year your birthday is treated as the last day of February (February 28) for the months-and-days breakdown, while the total-days count still reflects the true elapsed days including the missing February 29 in non-leap years.