Find how many years, months, and days separate a birth date from an as-of date. Both fields are calendar dates only — no clock time and no time zone. The default example is 15 January 2000 to 3 October 2026, which is 26 years, 8 months, and 18 days. This is a calendar estimate only, not a legal age determination.
Pick a birth date and an as-of date. The page counts whole years as the number of birthdays reached on or before the as-of date. A 29 February birthday is reached on 28 February in a year that is not a leap year.
After that last birthday, whole months are counted on the same day-of-month, or on the last day of a shorter month. Leftover calendar days after that month anniversary are the day count.
If the as-of date is before the birth date, the page rejects the pair. The same calendar day is 0 years, 0 months, and 0 days. Empty and impossible dates (such as 30 February) are rejected instead of rolled over. The calculator does not use a clock time, a time zone, or the visitor's current day as a moving result.
15 January 2000 to 3 October 2026 is 26 years, 8 months, and 18 days. The 26th birthday is 15 January 2026. Eight months later is 15 September 2026. Eighteen days remain to 3 October 2026. A Feb 29 birthday is reached on Feb 28 in a non-leap year.
Parse each date as year, month, and day numbers. Reject dates that are not real calendar days. Years = birthdays reached on or before the as-of date (Feb 29 birthday → Feb 28 in a non-leap year). After the last birthday, months advance on the same day-of-month or the last day of a shorter month. Days = leftover calendar days after that month anniversary. Same day is 0/0/0. As-of before birth is rejected.
A calendar estimate only, not a legal age determination. This age calculator uses two calendar dates and does not apply a clock time or a time zone. It is not legal, compliance, employment, or ID advice. GlobalToolHub assumes no liability for decisions made using these figures.
Years are the number of birthdays reached on or before the as-of date. After the last birthday, months advance on the same day-of-month, or on the last day of a shorter month. Leftover calendar days after that month anniversary are the day count. The default pair, 15 January 2000 to 3 October 2026, is 26 years, 8 months, and 18 days.
In a leap year the birthday is 29 February. In a year that is not a leap year, that birthday is reached on 28 February. So 29 February 2000 to 28 February 2021 is 21 years, 0 months, 0 days. The next day, 1 March 2021, is 21 years, 0 months, 1 day. On 29 February 2024 the age is 24 years, 0 months, 0 days.
A month is reached on the last day of that shorter month. From 31 January 2020 to 29 February 2020 (a leap February) the age is 0 years, 1 month, 0 days. From 31 January 2020 to 1 March 2020 it is 0 years, 1 month, 1 day.
The age is 0 years, 0 months, and 0 days. The page does not invent a partial day from a clock time.
The pair is rejected. Empty dates and impossible calendar dates (for example 30 February or 29 February 2023) are also rejected instead of being rolled to another day.
No. This is a calendar estimate only, not a legal age determination. It does not use a clock time or a time zone, and it is not legal, compliance, or ID advice.