Age Calculator
Find an exact age in years, months and days from a date of birth.
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- Nothing leaves your browser
Exact age
27 years, 4 months, 7 days
- Total months
- 328
- Total days
- 10,022
- Next birthday in
- 238 days
Results update as you type.
How exact age is worked out
Age is counted in completed units, largest first. The calculator counts how many whole calendar months have passed since the date of birth, then measures the days left over after the last of those months.
months = (to.year - from.year) x 12 + (to.month - from.month)
if from + months is later than to: months -= 1
days = to - (from + months)
years = months / 12, remaining months = months % 12
Adding a month clamps to the end of the target month, so 31 January plus one month is 28 or 29 February rather than spilling into March. That detail matters more than it looks: subtracting day numbers directly and borrowing from the previous month produces a negative day count whenever the birth date falls on a day that the borrowed month does not have, such as 31 January to 1 March.
Because the calculation walks real calendar dates rather than assuming a fixed 365-day year, leap days are counted correctly without any special case.
Frequently asked questions
How is exact age calculated?
Years are counted first, then whole months, then the remaining days. The calculator borrows from the previous calendar month when the day of the month has not yet been reached, which is why the day count varies depending on whether that month had 28, 30 or 31 days.
Does this handle leap years correctly?
Yes. Because the calculation walks real calendar dates rather than assuming a fixed 365-day year, leap days are counted automatically in both the total-days figure and the years, months and days breakdown.
What happens to a birthday on 29 February?
In non-leap years the birthday is treated as falling on 28 February, so someone born on 29 February 2004 counts as turning 22 on 28 February 2026. This end-of-month convention is what most date software uses. Some jurisdictions instead treat the birthday as 1 March for specific legal purposes, so check the rule that applies if an exact legal date matters.
Can I calculate age on a date other than today?
Yes. Change the second date from today to any other date, past or future, and the result recalculates as at that date.
Is my date of birth stored anywhere?
No. The calculation happens entirely in your browser and nothing is transmitted. There is no account, no analytics on the values you enter and no record kept.