How to use the age calculator
- 1Enter the Date of birth.
- 2Leave Age on as today, or pick another date. Press Today to reset it.
- 3Read the age in years, months and days, the totals in months, weeks, days and hours, and the Next birthday.
- 4Press Copy result to copy the age.
Born 15 May 1990, age on 5 October 2026
Date of birth 1990-05-15 · Age on 2026-10-05
36 years, 4 months, 20 days Total: 436 months · 1,898 weeks and 6 days · 13,292 days Next birthday: Saturday, 15 May 2027, in 222 days (turning 37) Born on a Tuesday
Exact age in years, months and days
The calculator counts whole months from the date of birth to the target date, then the days left over:
- Count complete months: from 15 May 1990 to 15 September 2026 is 436 months, or 36 years and 4 months.
- Count the days from that monthly anniversary to the target date: 15 September to 5 October is 20 days.
When a birth day doesn't exist in a month (the 31st in a 30-day month), that month's anniversary falls on its last day. Totals in days count real calendar days, including every 29 February in between, so they don't depend on an average month length.
Age on a specific date
Change Age on to any date in the past or future to answer questions such as "How old was I when I started school?" or "Will I be 18 on the exam date?". Forms with an age limit usually count completed years on a cut-off date: someone born on 2 October 2008 is 17 on 1 October 2026 and turns 18 the next day.
Age is counted in whole calendar days. The time of birth and time zones are ignored, as they are on official documents.
Age difference between two people
Enter the older person's date of birth as Date of birth and the younger person's as Age on. The result is the gap between them in years, months and days, and the totals give it in days or weeks.
For example, people born on 3 March 1985 and 20 November 1988 are 3 years, 8 months and 17 days apart. The gap stays the same throughout their lives, even though their ages in years differ by 3 for part of each year and by 4 for the rest.
Next birthday countdown
Next birthday shows the date and weekday of the coming birthday, how many days away it is, and the age you'll turn. If the target date is the birthday itself, it says so.
For a countdown to any other date, set Date of birth to today and Age on to the event: Total days is the number of days to go.
Leap years
A leap year has 366 days and adds 29 February. Years divisible by 4 are leap years, except century years, which must be divisible by 400: 2000 was a leap year, 1900 wasn't and 2100 won't be.
For someone born on 29 February, this calculator counts the birthday on 28 February in common years, so they turn a year older on 28 February 2027. Legal rules differ between countries: some treat 1 March as the birthday in common years. If the date matters for a legal age, check the rule where you live.
Is anything I enter stored?
This tool runs entirely in your browser. Your text is not uploaded to our servers.