Age Calculator
Give your date of birth and see your precise age broken down every way that matters: years, months and days; total weeks, days, hours and seconds; the day of the week you arrived; your zodiac sign and generation; and a live countdown to your next birthday. You can also calculate your age on any past or future date.
Worked example
Born 15 June 1990 at 08:30, measured on 7 June 2026: 35 years, 11 months, 23 days; about 13,141 days, 1,877 weeks, 315,378 hours, 1,135,362,600 seconds; next birthday in 8 days; born on a Saturday; Gemini; Millennial generation.
How age is calculated
Your age is the calendar distance between your date of birth and a reference date (today by default). The years, months and days are found by calendar subtraction rather than dividing total milliseconds: the calculator subtracts the birth day, month and year, then borrows from the next unit whenever a value goes negative. This handles months of different lengths and leap years automatically. For example, someone born on 31 January who wants their age as of 1 March has only spent one month and either 28 or 29 days in February depending on the year, and the calculator adjusts accordingly.
Age in hours, minutes and seconds
When you supply an optional birth hour and minute, the calculator measures the span from your exact birth moment to midnight at the start of the reference date. This gives a precise count of total hours and seconds. Without a birth time the calculator counts from midnight on your birth date. Either way, the result often surprises people: a 35-year-old has lived more than one billion seconds.
Zodiac sign, generation and day of the week
Your zodiac sign is determined by the Western tropical system: Aries runs from 21 March to 19 April, Taurus from 20 April to 20 May, and so on. The generation label uses the widely cited Pew Research definitions: Baby Boomers are born 1946-1964, Generation X from 1965-1980, Millennials from 1981-1996, and Generation Z from 1997-2012. The day of the week you were born is calculated using the Gregorian calendar proleptic algorithm, and is accurate for any date after 15 October 1582 when the Gregorian calendar came into use.
Counting down to your next birthday
The countdown finds the next calendar occurrence of your birth month and day after the reference date. If that date has already passed this year the counter rolls to the following year. People born on 29 February (leap day) experience their exact calendar birthday only in leap years: in other years the calculator finds 1 March as the next closest date, which is the more common convention for legal and milestone purposes. Change the "Age at date" field to see how the countdown shifts for any future reference point.
Finding your birth year from your age (reverse mode)
Switch the mode to "Find my birth year from my current age" if you know how old someone is but not their date of birth, which is common in genealogy, census research and some medical contexts. The calculator subtracts the entered age from the reference year to give an approximate birth year. The result may be off by one year depending on whether that person's birthday has already occurred in the reference year, so treat it as a range of reference-year minus age to reference-year minus age plus one.
Approximate age in 2026 by birth year
| Birth year | Approx. age in 2026 | Generation |
|---|---|---|
| 1940 | 85 | Silent Generation |
| 1950 | 75 | Silent Generation |
| 1955 | 70 | Baby Boomer |
| 1960 | 65 | Baby Boomer |
| 1965 | 60 | Generation X |
| 1970 | 55 | Generation X |
| 1975 | 50 | Generation X |
| 1980 | 45 | Millennial |
| 1985 | 40 | Millennial |
| 1990 | 35 | Millennial |
| 1995 | 30 | Millennial |
| 2000 | 25 | Generation Z |
| 2005 | 20 | Generation Z |
| 2010 | 15 | Generation Z |
| 2015 | 10 | Generation Alpha |
| 2020 | 5 | Generation Alpha |
Exact age depends on your birthday relative to June 2026.
Frequently asked questions
How do you handle leap years?
Leap days are included in every day, hour and second count, and the calendar-based years/months/days breakdown uses the actual length of each month, so February having 28 or 29 days is always handled correctly. A 29 February birthday is calculated by looking for the next occurrence of that exact date in a leap year for the birthday countdown.
Can I find my age on a past or future date?
Yes. Fill in the "Age at date" field with any date to calculate how old you were or will be on that day. Leave it blank to use today as the reference. For future dates the calculator counts forward exactly as it does for the past.
Why does my age in seconds seem so large?
Each year contains about 31.5 million seconds (365.25 days x 86,400 seconds). A person who is 35 years old has lived roughly 35 x 31.5 million, which is more than 1.1 billion seconds. The number grows quickly because seconds are very small units relative to human lifespans.
What generation am I in?
The calculator uses the Pew Research Center generational boundaries: Silent Generation (born before 1946), Baby Boomers (1946-1964), Generation X (1965-1980), Millennials (1981-1996), Generation Z (1997-2012), and Generation Alpha (2013 onward). Different researchers use slightly different cut-off years, so if you were born near a boundary you may identify with either label.
How accurate is the zodiac sign?
The calculator uses the Western tropical zodiac, where sign boundaries are fixed calendar dates (for example Scorpio runs from 23 October to 21 November). If your birthday falls exactly on a boundary date, the sign can shift by a day depending on the exact year, because the sun crosses the ecliptic at slightly different clock times each year. For precise sun-sign calculation you would need the exact birth time and a full ephemeris lookup.
How does the reverse mode work?
In "Find my birth year" mode, the calculator subtracts your entered age from the reference year. Because the calculation does not know your birthday within the year, the result may be off by one: someone who turns 35 in August but whose reference date is June is still 34, so their birth year would be one earlier than the formula suggests. Use the result as "born in year Y or Y+1" rather than a definitive answer.