Age Calculator
Find an exact age from two dates, including total days lived, the next birthday countdown and the weekday you were born.
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Fill in the fields and the answer updates instantly — no need to press anything.
How the age calculation works
An exact age is not simply days divided by 365.25 — it is counted in whole calendar years, then whole months, then leftover days, which is how birthdays actually work.
Total days lived is the straightforward difference between the two dates, and it accounts for leap years automatically because every 29 February is included.
The next birthday is the same month and day in the current year, or the following year if that date has already passed.
Worked example
Born 14 June 1990, aged at 1 January 2026.
- →Whole years: 35 (birthday in June not yet reached)
- →From 14 June 2025 to 1 January 2026: 6 months
- →1 January − 14 December = 18 days
Answer: 35 years, 6 months and 18 days — about 12,985 days.
Age FAQs
How do I calculate age on a future date?
Change the reference date. It is useful for paperwork, retirement dates or working out how old someone will be at an event.
Why is my age in months different from years × 12?
Because the extra months are counted on the calendar, not as a fraction of a year. That is why 35 years and 6 months is 426 months, not 426.something.
Does this handle 29 February birthdays?
Yes. In non-leap years the reference date rolls to 1 March, which matches how most jurisdictions treat leap-day birthdays.
Age Calculator is part of the math calculators collection on Calcora, alongside 7 other tools. Results are calculated in your browser and are for information only — see our disclaimer.
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