Age Calculator
Find out your exact age in years, months, days, weeks, and days alive — plus how long until your next birthday.
Results update as you change your date of birth. Today's date is taken from your device clock; if it's wrong, the age will reflect that.
Formula
Age is calendar arithmetic between your date of birth and today's date — counted as whole years (you're 30 from your 30th birthday until the day before your 31st), then whole months and days from your last birthday for the precision breakdown. The day-of-week-born is computed from the Gregorian calendar using your DOB. Leap-year birthdays (29 February) celebrate on 28 February in non-leap years.
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Frequently asked questions
How is age calculated?▾
By comparing your date of birth to today using calendar arithmetic. The years/months/days breakdown counts whole calendar years, then whole months from your last birthday, then days from there. Total days alive is the simple count of 24-hour periods since you were born.
Why does my 'age in days' jump on my birthday?▾
It doesn't, actually — it ticks up by 1 every day. Your years figure jumps on your birthday (from N to N+1), but the day count is steadily incrementing. Some people notice the years change and mistake it for a discontinuity in days.
What about 29 February birthdays?▾
Leaplings (born on 29 February) celebrate their birthday on 28 February in non-leap years in this calculator. Some leaplings prefer 1 March; either is reasonable, and the legal rule varies by jurisdiction (England + Wales: 1 March; Scotland: 28 February; the Republic of Ireland: 28 February).
Is my age in years rounded down?▾
Yes — that's the standard convention. You're 30 from your 30th birthday until the day before your 31st. The years/months/days breakdown shows the precise interval.
How does the day-of-week calculation work?▾
Standard ISO-week algorithm: the calculator computes the day of the week from the date of birth using the Gregorian calendar. It works for dates back to 1583 (when most of Europe adopted the Gregorian calendar); earlier dates require Julian-calendar treatment which this calculator doesn't do.
Can I use this for pension or retirement age?▾
Yes — enter your date of birth to see your current age. UK State Pension age depends on when you were born and is independent of this calculator's output: most people born in the 1960s and later face state pension age 67 or higher; check gov.uk for your specific date.