Age difference calculator
Compare two birth dates in calendar years, months and days, plus total days.
Calendar arithmetic only. Birth times and time zones are not included.
How this works
The earlier civil date is subtracted from the later date using the Gregorian calendar. Calendar months clamp to the last valid day when needed. Total days use UTC-midnight dates to avoid daylight-saving drift.
An example
January 1, 2000 to January 1, 2005 is 5 calendar years, or 1,827 days because the interval includes two leap days.
Good to know
Why do months have different lengths?+
The calculation uses calendar months, not a fixed 30-day month.
Does it judge a relationship?+
No. It only compares dates. It makes no recommendation about relationships.
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