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What this calculator does
Calculate age from a birth date and a reference date.
How to use this calculator
- Enter date of birth and the date to calculate against.
- Review the calculation assumptions before using the result.
- The result gives completed years and the remaining months and days.
How to calculate
Choose the calculation mode where available, then enter the values requested by the age calculator. Results update immediately.
Worked example
With the example values shown above, the exact age is 36 years 2 months 7 days, and the total months is 434 months 7 days, and the total weeks is 1,888.14 weeks.
Understanding your result
The result gives completed years and the remaining months and days.
- Time-zone and inclusive-date rules can differ in legal contexts.
- Double-check values and units before calculating.
Frequently asked questions
What does this age calculator do?
Calculate age from a birth date and a reference date.
How do I use this age calculator?
Enter date of birth and the date to calculate against.
What does the result mean?
The result gives completed years and the remaining months and days.
What should I check before relying on it?
Time-zone and inclusive-date rules can differ in legal contexts.
Why does my age change right around my birthday depending on the date I check?
Your completed age only increases once your birth month and day have occurred in the current year — checking the day before your birthday correctly shows one year less than checking the day after.
Does this account for leap years?
Yes — the calculation walks through actual calendar months and days, so a February 29th birth date or a leap year in the elapsed range is handled correctly rather than assumed away.
Can I calculate my age on a specific past or future date, not just today?
Yes — change the 'calculate age on' date to any date you need, such as a policy start date or a future eligibility date, and the result recalculates for that reference date.