Age Calculator
Find your exact age in years, months and days on any date
Age is the number of complete years since the date of birth, so it goes up on each birthday. Someone born on January 1, 2000 is 26 years, 8 months and 24 days old on September 25, 2026, which is 9,764 days.
Age calculator
LiveHow to calculate age
Exact age is counted like a stopwatch with three dials. First count the complete years since the birth date, then the complete months since the last birthday, then the days since the last month-day. The calculator above does this for any date of birth and any "age on" date, which defaults to today. For a plain count of days between two dates, the days between dates calculator is quicker, and the date calculators section lists every related tool.
- Subtract the birth year from the current year: 2026 − 1990 = 36.
- Subtract the birth month from the current month. If the result is negative, take 1 from the years and add 12 to the months.
- Subtract the birth day from the current day. If that is negative, take 1 from the months and add the number of days in the previous month.
- Example: born June 15, 1990, on September 25, 2026: 36 years, 9 − 6 = 3 months and 25 − 15 = 10 days.
A borrowing example: born January 31, 1990, age on March 15, 2026. The day difference is 15 − 31 = −16, so the calculator borrows the 28 days of February 2026, giving 12 days, and the months drop from 2 to 1. The age is 36 years, 1 month and 12 days.
Alongside the age, the calculator shows the total in days (the exact number of days between the two dates), whole weeks (days ÷ 7, rounded down) and whole months; the next birthday with a countdown in days and the age it brings; and the weekday you were born on. The age-on date must be on or after the date of birth.
How do I calculate age in Excel or Google Sheets?
Use =DATEDIF(A2,TODAY(),"Y") for completed years, with the date of birth in A2; the "YM" and "MD" units give the extra months and days.
To build the full years, months and days line with the age-on date in B2:
=DATEDIF(A2,B2,"Y")&" years, "&DATEDIF(A2,B2,"YM")&" months, "&DATEDIF(A2,B2,"MD")&" days"
With January 1, 2000 in A2 and September 25, 2026 in B2, it returns 26 years, 8 months, 24 days, the same as the calculator. For the total in days, =B2-A2 gives 9,764.
- DATEDIF is hidden from Excel's formula suggestions but still works. Microsoft warns that the "MD" unit can return inaccurate results, so check month-end birthdays by hand.
- YEARFRAC returns age as a decimal number of years, handy for charts but not for legal ages.
- Google Sheets accepts the same DATEDIF formulas.
What year was I born if I am 30?
If you are 30 on September 25, 2026, you were born between September 26, 1995 and September 25, 1996: in 1996 if your birthday has already come this year, in 1995 if it has not.
The quick rule is birth year = current year − age, minus one more if this year's birthday is still ahead. Reversing it gives the age: 2026 − 1996 = 30 for a birthday already reached. The same logic for other ages, on September 25, 2026:
| Age | Born between |
|---|---|
| 18 | September 26, 2007 – September 25, 2008 |
| 21 | September 26, 2004 – September 25, 2005 |
| 30 | September 26, 1995 – September 25, 1996 |
| 40 | September 26, 1985 – September 25, 1986 |
| 50 | September 26, 1975 – September 25, 1976 |
| 65 | September 26, 1960 – September 25, 1961 |
A birth year alone cannot pin down an exact age, which is why age checks, school cutoffs and benefit rules ask for the full date of birth. Enter yours above to see the exact figure.
Age examples on September 25, 2026
Results as the calculator shows them, with total days verified in Python. A birthday on the age-on date counts as a completed year.
| Date of birth | Age | Total days | Next birthday |
|---|---|---|---|
| January 1, 2000 | 26 years, 8 months, 24 days | 9,764 | January 1, 2027 (in 98 days, turns 27) |
| June 15, 1990 | 36 years, 3 months, 10 days | 13,251 | June 15, 2027 (in 263 days, turns 37) |
| December 31, 1985 | 40 years, 8 months, 25 days | 14,878 | December 31, 2026 (in 97 days, turns 41) |
| May 10, 1980 | 46 years, 4 months, 15 days | 16,939 | May 10, 2027 (in 227 days, turns 47) |
| September 25, 1961 | 65 years, 0 months, 0 days | 23,741 | Today, turns 65 |
| September 25, 2008 | 18 years, 0 months, 0 days | 6,574 | Today, turns 18 |
| September 26, 2008 | 17 years, 11 months, 30 days | 6,573 | September 26, 2026 (in 1 day, turns 18) |
| February 29, 2004 | 22 years, 6 months, 27 days | 8,244 | February 28, 2027 (in 156 days, turns 23) |
| December 1, 2025 | 0 years, 9 months, 24 days | 298 | December 1, 2026 (in 67 days, turns 1) |
When does someone born on February 29 have a birthday?
In leap years on February 29; in the three common years between, this calculator counts the birthday on February 28, both for the countdown and for completed years. Leap years are years divisible by 4, except century years not divisible by 400, so the next ones are 2028, 2032 and 2036. Someone born on February 29, 2004 turns 23 on February 28, 2027 in this calculator, and reaches a true 24th birthday on February 29, 2028, after 8,766 days.
Legal systems do not all agree on which day counts in a common year: some treat February 28 as the birthday and others March 1. If an exact legal age matters, for a license, a contract or benefits, check the rule where you live.
Age milestones in the United States
Federal ages that people often look up. State laws and program rules can differ and change, so confirm with the relevant agency.
| Age | Milestone |
|---|---|
| 18 | Voting age for federal, state and local elections (26th Amendment) |
| 21 | Minimum legal drinking age in every state |
| 26 | Young adults can stay on a parent's health plan until turning 26 under the Affordable Care Act |
| 50 | Catch-up contributions allowed for 401(k) plans and IRAs |
| 59½ | Withdrawals from IRAs and most 401(k) plans no longer face the 10% early-withdrawal penalty |
| 62 | Earliest age to claim Social Security retirement benefits, at a reduced amount |
| 65 | Medicare eligibility for most people |
| 67 | Full retirement age for Social Security if you were born in 1960 or later |
| 73 | Required minimum distributions from retirement accounts begin under current law |
How do I find my age in days, weeks or months?
Read the Total result: it gives your age as exact days, whole weeks and whole calendar months, for example 9,764 days, 1,394 weeks and 320 months for someone born on January 1, 2000, on September 25, 2026. Some people celebrate a 10,000-day milestone, a little over 27 years: for a January 1, 2000 birth it falls on May 19, 2027. The add days to date calculator finds it for any birthday, and the time converter turns days into hours or seconds.
International age vs traditional counting
This calculator uses the international method, in which a baby is 0 at birth and gains a year on each birthday. Some East Asian traditions counted a newborn as 1 and added a year every New Year. South Korea, the best-known example, adopted international age for legal and administrative purposes in June 2023.
Birth dates and time zones
Age is based on the date of birth recorded where you were born. The calculator works with dates only, so a birth just after midnight in Mumbai counts on that local date, even though it was still the previous evening in New York; the time zone converter shows that gap for any pair of cities.
When an exact age matters
- Employment and HR: confirming minimum working ages, retirement-plan eligibility and age-based benefit changes.
- Legal documents: contracts, wills and court filings sometimes need age in completed years on a specific date, not today.
- School and sports: enrollment cutoffs and youth leagues use an age on a set date, which you can enter in the Age on field.
- Health: pediatric growth charts use age in months, and screening guidelines start at particular ages.
- Travel: child fares and passport rules depend on age on the travel date.
To count the days between any two other dates, such as a hire date and today, use the days between dates calculator.
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Further reading
- Gregorian calendarWikipedia
Age calculator FAQs
Short, exact answers to what people ask most.
How do I calculate my exact age?
Count the complete years since your date of birth, then the complete months since your last birthday, then the remaining days. The calculator does this automatically and also shows the total in days, weeks and months.
How old is someone born in 2000 in 2026?
On September 25, 2026, someone born on or before September 25, 2000 is 26, and someone born later in 2000 is still 25. Someone born on January 1, 2000 is exactly 26 years, 8 months and 24 days old.
How many days old am I?
Enter your date of birth and the calculator shows the total days next to your age. For example, a person born on June 15, 1990 is 13,251 days old on September 25, 2026.
How does the calculator handle a February 29 birthday?
In common years it counts down to February 28 as the next birthday, and in leap years to February 29. A person born on February 29, 2004 reaches a true 24th birthday on February 29, 2028.
Can I calculate age on a past or future date?
Yes. Change the Age on date to any day on or after the date of birth, for example an enrollment cutoff or a retirement date, and all results update.
What day of the week was I born?
The Born on a result shows the weekday of your birth date. For example, January 1, 2000 was a Saturday and June 15, 1990 was a Friday.
How old is someone born in 1990?
On September 25, 2026, someone born in 1990 is 36 if their birthday has passed and 35 if it is still ahead. A June 15, 1990 birthday gives exactly 36 years, 3 months and 10 days.
How old is someone born in 2010?
On September 25, 2026, someone born in 2010 is 16 if their birthday has passed and 15 if not. A March 3, 2010 birthday gives 16 years, 6 months and 22 days.
How many weeks old is a 1-year-old?
A baby born on September 25, 2025 is 365 days, or 52 weeks and 1 day, old on its first birthday. If February 29 falls within the first year, the figure is 52 weeks and 2 days.
How old is someone who is 10,000 days old?
Someone born on January 1, 2000 reaches 10,000 days on Wednesday, May 19, 2027, at 27 years, 4 months and 18 days. The years and months differ slightly for other birth dates because of leap years.
What is my age in months?
Your age in months counts complete calendar months since birth. Someone born on January 1, 2000 is 320 months old on September 25, 2026, a figure the calculator shows in the Total result.
Related conversions
Dates follow the Gregorian calendar; examples were checked with Python's datetime library, spreadsheet functions follow Microsoft Excel and Google Sheets documentation, and US age milestones come from the US Constitution, the Social Security Administration, Medicare.gov and the IRS. Last updated . How we verify our numbers.