Age Calculator
Calculate your exact age in years, months and days, plus see how long remains until your next birthday.
Choose the date you want to measure
- Enter a date of birth.
- Choose the calculation date. It starts with today’s date on your device, but you can choose a past or future date.
- Select Calculate Age to see calendar years, months and days, completed months and weeks, total days and the next birthday countdown.
Two dates, two different answers
For a birth date of 15 September 2000, the age on 14 September 2026 is 25 years, 11 months and 30 days. On 15 September 2026, it becomes exactly 26 years. The day and month matter; subtracting the birth year alone misses the birthday boundary.
Month ends and leap-day birthdays
The calculation uses completed calendar months followed by the remaining days. If the birth day does not exist in a target month, it uses that month’s last day. For example, 31 January to 28 February 2026 counts as one month, and 31 January to 1 March counts as one month and one day.
For a 29 February birthday, this tool uses 28 February in non-leap years. That is a calculation convention, not a ruling about a legal birthday or an organisation’s eligibility rules.
Understand the totals
Total days measure calendar-date separation, with the same date giving zero. Weeks are complete seven-day periods, rounded down. Total months count complete calendar months, so they are not total days divided by 30. The birthday countdown is measured from the calculation date you selected, which may differ from today.
Age calculation questions
Can I calculate age on a future date?
Yes. Choose that future date in Calculate age on. A date earlier than the birth date is rejected.
Does it include the time of birth?
No. Inputs are calendar dates, without hours, minutes or a birth timezone.
Why might another age calculator differ?
Month-end handling, leap-day conventions and inclusive day counting can differ. Compare the conventions as well as the dates.
Can I use this for an official age requirement?
Use it as a date check, then follow the organisation’s own rules and required documents. The calculator does not determine legal eligibility.
Privacy and other tools
The tool calculates dates in your browser; it does not require a name or account. Read the Privacy Policy for website data handling, or return to all tools.