Age Calculator: Exact Age in Years, Months and Days

Enter a date of birth to get the exact age in years, months and days, the number of days lived, the day of the week of birth and the next birthday.

Date of birthExample value: replace it with the date of your choice.

Age on

On Thursday 8 October 2026, someone born on Monday 14 May 1990 is 36 years, 4 months and 24 days old.

Exact age: 36 years, 4 months and 24 days
Days lived: 13,296
In weeks: 1,899 weeks and 3 days
Full months: 436 months
Hours (approx.): 319,104 hours
Born on a: Monday
Next birthday: Friday 14 May 2027 (in 218 days, turning 37)
10,000th day: Friday 29 September 2017 (3,296 days ago)
20,000th day: Tuesday 14 February 2045 (in 6,704 days)

Ages in days

Age	Number of days
1 year	365 or 366
10 years	3,652 or 3,653
18 years	6,574 or 6,575
20 years	7,305
30 years	10,957 or 10,958
40 years	14,610
50 years	18,262 or 18,263
100 years	36,524 or 36,525

The one-day difference depends on how many 29 Februaries fall in the period. These values apply to periods that do not span 1900 or 2100, which are not leap years.

Your 10,000th day

Some people like to celebrate their 10,000th day of life. It comes at around 27 years and 4 months, since 10,000 days is about 27.4 years. The calculator gives you the exact date, as well as your 20,000th day at about 54 years and 9 months. Someone born on 14 May 1990 turned 10,000 days old on Friday 29 September 2017.

Frequently asked questions

How do I work out my age in months?

Multiply the years by 12 and add the months since your last birthday. At 36 years and 4 months, you have lived 436 full months. The calculator shows this on the “Full months” line.

What day of the week was I born on?

It is shown on the “Born on a” line. For example, 14 May 1990 was a Monday.

Does the time of birth matter?

No. The calculation is done in whole days: the age changes on the birthday, whatever time you were born. In English law, a person attains a given age at the start of the relevant anniversary of their birth.

Can I calculate an age on another date?

Yes: change the “Age on” field. You can find out how old someone was at a particular event, or how old they will be on a given day.

Is my date of birth stored?

No. The calculation runs in your browser; the date is neither sent nor saved.

How to calculate an exact age

First count the full years up to the last birthday, then the full months since that birthday, and finally the remaining days. Example for someone born on 14 May 1990, on 8 October 2026:

The last birthday was on 14 May 2026: 36 years.
From 14 May to 14 September 2026: 4 months.
From 14 September to 8 October: 24 days.

Result: 36 years, 4 months and 24 days.

Age in days

The number of days lived is the difference between the date of birth and the reference date. Count 365 days per full year, plus one day for each 29 February. Between 14 May 1990 and 14 May 2026 there were nine 29 Februaries (1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020 and 2024): 36 × 365 + 9 = 13,149 days. Add the 147 days from 14 May to 8 October: 13,296 days.

Born on 29 February

In years without a leap day, the calculator puts the birthday on 28 February, the last day of the month. Some people prefer to celebrate on 1 March; it is a matter of taste and does not change the number of days lived.