Age Calculator

1. 1Enter the date of birth.
2. 2Leave the second date as today, or set it to work out an age on a particular date.
3. 3Read the exact age, followed by the totals and the next birthday countdown.

Age is counted the way people actually count it: whole years first, then whole months, then the days left over. The tool finds the most recent birthday, counts the whole months since it, and the days remaining after the last whole month.

Months are counted on the real calendar, so their different lengths are respected. When a month is too short for the birth day, the month is complete on its last day: a person born on 31 January is 1 month old on 28 February in a common year, because February has no 31st, and 1 month and 1 day old on 1 March.

Leap years are handled by the calendar itself rather than by assuming 365.25 days. Someone born on 29 February has their anniversary treated as 1 March in common years, which is the most widely used convention.

Someone born on 15 March 2001, checked on 5 September 2026

1. Enter 15 March 2001 as the date of birth.
2. Leave the second date as 5 September 2026.

Result: 25 years, 5 months and 21 days — 9,305 days in total, with the next birthday 191 days away.

• Set the second date to find an age on a particular day — a school entry cut-off, an exam date or a pension date.
• Use the total in days or weeks for things that are counted that way, such as a baby's age in the first months.
• Check the next-birthday countdown when planning; it accounts for month lengths and leap years.
• For the length of time between any two events, not just birthdays, the same calculation works: enter the earlier date first.

• How to calculate an exact age in years, months and days
• Dog years to human years: why the ×7 rule is wrong
• How to calculate age on a specific date (for exam and job eligibility)
• How to count the days between two dates