How old am I in days?

Enter your birth date; the 'Total days lived' line counts every day from your birth to today. Someone born on 1 January 2000 had lived 9,738 days by 30 August 2026.

How do I calculate exact age?

Subtract the birth year, month and day from the current ones, borrowing a month (and its days) when the day comes out negative, and a year when the month does. The page does this with the real calendar.

What day of the week was I born?

The 'Born on' line gives it. 1 January 2000 was a Saturday.

How old will I be on a future date?

Change the 'as of' date to that day. The page gives your exact age then, in the same years, months and days.

When will I be 10,000 days old?

Add 10,000 days to your birth date — the add-days calculator does it in one step. Born on 1 January 2000, you reach 10,000 days on 19 May 2027, at about 27 years and 4½ months.

How many months old is a baby?

Read the 'Total months' line. A baby born on 15 March 2026 is 0 years, 6 months, 17 days old on 2 October 2026 — six whole months and 17 days.

How do I calculate age in Excel?

=DATEDIF(birth date, today, "y") gives whole years, "ym" the months after those years and "md" the days after those months. Microsoft advises against the "md" option because of known limitations with some dates, which is one reason to check here.

Age Calculator: Exact Age in Years, Months and Days

Exact age in years, months and days on any date, with total months, weeks and days and the next birthday.

Inputs

Date of birth

As of date

Include CalculateEveryday mark

Age

26 years, 7 months, 29 days

Born on: Saturday, January 1, 2000
Total months: 319 months and 29 days
Total weeks: 1,391 weeks and 1 day
Total days lived: 9,738
Next birthday: Friday, January 1, 2027 — in 124 days, turning 27

Use this calculator on your own site

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Shows a small CalculateEveryday bar, with a credit link under the calculator

What each Age input means

Date of birth: The date of birth. Any date in the past works; a 29 February birthday is handled, with a note on how common years treat it.
As of date: The day to measure the age on — today by default. Set a past date for an age back then, or a future one for the age on a deadline, a retirement date or a birthday party.

Age formula

age = as-of date − date of birth, as whole years, then whole months, then days

\text{age} = (y_2 - y_1)\,\text{years} + (m_2 - m_1)\,\text{months} + (d_2 - d_1)\,\text{days} \text{ (with borrowing)}

Age is counted the way a calendar counts it: whole years first, then whole months, then the days left over. When the day of the month on the 'as of' date is smaller than the birth day, a month is borrowed and its length added to the days — so the answer follows real month lengths and leap years rather than dividing by 365. Alongside the years-months-days figure, the page gives the age as total months, total weeks and total days lived, the weekday you were born on, and the date and weekday of the next birthday with the number of days to go. Set the 'as of' date to any day — past or future — for an age on that date.

Age worked example

Someone born on Saturday 1 January 2000 is, on 30 August 2026, 26 years, 7 months and 29 days old — 319 months, or 9,738 days. Their next birthday, their 27th, is Friday 1 January 2027, 124 days away.

More Age examples

Born on Sunday 15 July 1990, on 2 October 2026 a person is 36 years, 2 months, 17 days old: 434 whole months, and 13,228 days lived. Their 37th birthday is Thursday 15 July 2027, 286 days away.

A leap-day birthday, 29 February 2004: on 2 October 2026 the age is 22 years, 7 months, 3 days. With no 29 February in 2027, the next birthday is counted as Monday 1 March 2027.

Where the Age calculator can give the wrong answer

A 29 February birthday has no date in common years; the page counts 1 March then and notes it. Some laws use 28 February instead.
Total days lived counts the midnights from birth to the 'as of' date; it differs from years × 365 by the leap days crossed.
An 'as of' date before the birth date is rejected rather than giving a negative age.
In some East Asian traditions a person is one year old at birth; this page counts the international way, from zero.

Spotted a mistake? Tell us

Age reference table

Day-count milestones, and when someone born on 1 January 2000 reaches them
Days old	About this many years	Born 1 Jan 2000: the date
1,000	2.74	Friday 27 September 2002
5,000	13.69	Monday 9 September 2013
10,000	27.38	Wednesday 19 May 2027
15,000	41.07	Friday 25 January 2041
20,000	54.76	Sunday 4 October 2054
25,000	68.45	Tuesday 12 June 2068
30,000	82.14	Thursday 19 February 2082

Source: Gregorian calendar arithmetic; years = days ÷ 365.2425, the average Gregorian year

Age FAQ

: Enter your birth date; the 'Total days lived' line counts every day from your birth to today. Someone born on 1 January 2000 had lived 9,738 days by 30 August 2026.
: Subtract the birth year, month and day from the current ones, borrowing a month (and its days) when the day comes out negative, and a year when the month does. The page does this with the real calendar.
: The 'Born on' line gives it. 1 January 2000 was a Saturday.
: Change the 'as of' date to that day. The page gives your exact age then, in the same years, months and days.
: Add 10,000 days to your birth date — the add-days calculator does it in one step. Born on 1 January 2000, you reach 10,000 days on 19 May 2027, at about 27 years and 4½ months.
: Read the 'Total months' line. A baby born on 15 March 2026 is 0 years, 6 months, 17 days old on 2 October 2026 — six whole months and 17 days.
: =DATEDIF(birth date, today, "y") gives whole years, "ym" the months after those years and "md" the days after those months. Microsoft advises against the "md" option because of known limitations with some dates, which is one reason to check here.