Age Calculator
Exact age in years, months, days and total time lived.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Age
- 32 years, 1 months, 13 days
- Total days lived
- 11,731
- Total weeks
- 1,675
- Born on a
- Wednesday
- Next birthday
- 2027-06-15 (322 days)
Quick answer
Your age is the number of complete years since your date of birth, with the leftover months and days added for an exact figure. Count whole years first, then whole months, then the remaining days. Someone born on 1 March 2008 is 18 years, 7 months and 23 days old on 24 October 2026, having lived 6,811 days.
What the Age calculator does
Enter a date of birth and the calculator returns the exact age in years, months and days, the total days and weeks lived, the day of the week of birth, and how long until the next birthday. Change the "age on" date to find someone's age on a past or future date – the day a form was signed, a school entry cut-off, or a retirement date.
Ages are counted the way calendars and almost all legal systems count them: you gain a year on each birthday, and months are calendar months rather than fixed 30-day blocks. Because months have different lengths, "1 month and 3 days" can mean a different number of total days depending on which months are involved; the total-days figure removes that ambiguity.
To measure the gap between any two dates that are not a birthday, use the date difference calculator. For working days only, use the business days calculator.
The formula
Age = complete years from birth date to target date, then complete months, then remaining days Total days = target date − birth date (in days)
| Symbol | Meaning | Unit |
|---|---|---|
| birth date | Date of birth in YYYY-MM-DD format | date |
| target date | The date to measure age on; defaults to a set date you can change to today | date |
| total days | Exact count of days between the two dates, including leap days | days |
This uses the proleptic Gregorian calendar, the calendar in civil use worldwide. A person born on 29 February is treated as having a 1 March birthday in common years; legal rules on this vary by country, so check local law if it matters for a contract or eligibility date. Results are not reliable for dates before a country adopted the Gregorian calendar (1752 in Britain and its colonies).
Worked examples
Checking whether someone is 18
A school administrator checks the age of a student born on 1 March 2008 on 24 October 2026.
Inputs
- Date of birth2008-03-01 YYYY-MM-DD
- Age on date2026-10-24 YYYY-MM-DD
Result
- Age18 years, 7 months, 23 days
- Total days lived6,811
- Total weeks973
- Born on aSaturday
- Next birthday2027-03-01 (128 days)
The student turned 18 on 1 March 2026 and is 18 years, 7 months and 23 days old. The next birthday is 128 days away.
Age for a pension or benefit date
Someone born on 31 January 1961 wants their exact age on 24 October 2026.
Inputs
- Date of birth1961-01-31 YYYY-MM-DD
- Age on date2026-10-24 YYYY-MM-DD
Result
- Age65 years, 8 months, 23 days
- Total days lived24,007
- Total weeks3,429
- Born on aTuesday
- Next birthday2027-01-31 (99 days)
They are 65 years, 8 months and 23 days old, with 24,007 days lived. Retirement and benefit ages are set by each scheme, so compare this date against the official rules for your country.
Leap-day birthday
A person born on 29 February 2000 checks their age on 28 February 2026, a non-leap year.
Inputs
- Date of birth2000-02-29 YYYY-MM-DD
- Age on date2026-02-28 YYYY-MM-DD
Result
- Age25 years, 11 months, 30 days
- Total days lived9,496
- Total weeks1,356
- Born on aTuesday
- Next birthday2026-03-01 (1 days)
The calculator shows 25 years, 11 months and 30 days, with the 26th birthday falling on 1 March. If your jurisdiction counts the birthday as 28 February instead, the person would already be 26.
Why two age calculators can disagree
- Month-end birthdays. From 31 January, one month later has no 31st in most months, so tools differ on whether a month is complete on 28 February, 1 March or the last day of the month. For birthdays on the 29th to 31st, check the total-days figure, which is unambiguous.
- Leap days. Total days include every 29 February between the two dates, so dividing total days by 365 overstates age slightly over long spans.
- Inclusive counting. Some tools count both the start and end date. Here the birth date counts as day 0, so a baby is 1 day old on the day after birth.
- Time zones and birth times. This works in whole dates. A birth just before midnight in one time zone may be a different date elsewhere.
Age-counting systems around the world
Nearly every country now uses the international system above, where you are 0 at birth and gain a year on each birthday. South Korea formally switched its legal and administrative age to this system in June 2023, ending the official use of "Korean age", in which a baby counted as 1 at birth and everyone gained a year on 1 January. Traditional East Asian age reckoning is still used informally in some places, so an age given in conversation may be one or two years higher than the figure here.
Uses for an exact age
- Eligibility cut-offs: school entry, youth sports divisions, voting, driving and alcohol ages.
- Health: pediatric growth charts and vaccine schedules use age in months or weeks for young children.
- Finance: pension, Social Security and required minimum distribution rules hinge on exact birthdays – the Social Security calculator uses your claiming age.
- Milestones: 10,000 days old falls around 27 years and 4 months; set the "age on" date forward to find yours.
How to use the Age Calculator
- 1Enter the date of birth as YYYY-MM-DD (for example 1994-06-15).
- 2Set the "age on" date to today, or to any past or future date you want the age for.
- 3Read the exact age in years, months and days, then the total days and weeks.
- 4Check the next-birthday line for the date and the number of days remaining.
Frequently asked questions
How do I calculate my exact age?
Subtract your birth year from the current year, and take off one if your birthday has not happened yet this year. Then count the full months since your last birthday and the days since the last monthly date.
How many days old am I?
Enter your birth date and today's date; the total days lived line gives the exact count including leap days. On their 30th birthday most people have lived 10,957 or 10,958 days, depending on how many 29 Februaries fell in that span.
When does someone born on 29 February have a birthday?
In leap years, on 29 February. In other years this calculator uses 1 March; some people and some legal systems use 28 February instead.
What day of the week was I born?
The "Born on a" line shows it. For example, 15 June 1994 was a Wednesday.
Can I calculate age on a future date?
Yes. Set the "age on" date to any future date to see how old someone will be then, such as on a wedding or graduation day.
References
- Calendars (Explanatory Supplement to the Astronomical Almanac) — US Naval Observatory / University Science Books
- ISO 8601 – Date and time format — International Organization for Standardization
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
- Report an error