Two calculation modes
- My age: enter your date of birth; the tool gives your exact age in years, months and days as of today.
- Between two dates: enter a start date and an end date to get the precise duration between them.
How is age calculated?
The calculation works the way you count on a calendar: first full years, then full months, then the remaining days. It takes into account the real length of each month and leap years. This avoids the classic mistake of dividing a number of days by 365, which is off by almost a day every four years.
| From | To | Result |
|---|
| 15 March 2000 | 15 March 2026 | 26 years |
| 10 January 2026 | 25 April 2026 | 3 months and 15 days |
| 1 January 2026 | 1 January 2027 | 1 year, or 365 days |
Special cases
- Born on 29 February: in non-leap years, the legal birthday is generally set to 28 February or 1 March depending on the country. The count in days remains exact in every case.
- Ends of months: from 31 January to 28 February, a full calendar month has not passed. Conventions vary between fields such as banking, employment law and insurance; if something is at stake, refer to the rule that applies to your contract.
Common uses
- Checking a minimum or maximum age for an enrolment, a competition or an entitlement.
- Calculating length of service at a company or the duration of a contract.
- Counting the days left before a deadline, a departure or an event.
- Knowing a child's exact age in months, useful for medical follow-up in the early years.
Privacy
A date of birth is personal data. Here, everything is calculated in your browser: nothing is sent or kept.
Frequently asked questions
Is my data saved?
No, everything is calculated in your browser. Nothing is sent or kept.
Are leap years taken into account?
Yes. The calculation follows the real calendar, with the true length of each month and 29 February in leap years.
Is the end date included in the calculation?
The result gives the time elapsed between the two dates, as you count an age. To include the last day, as is sometimes done for a length of stay, add one day.
Can I calculate a future date?
Yes, in "Between two dates" mode: choose today as the start date and the deadline as the end date.