Age Calculator + Date Diff Online
How old are you? Or how much time between any two dates? Years, months, days, weeks, hours, minutes.
Tip
For someone's age, leave "To" on today. To count days until a deadline, set "From" to today and "To" to the future date.
Age calculator vs date diff — same engine, two use cases
An age calculator is just a specific case of a date difference (datediff) calculator: from a birthdate to today. The same arithmetic works for any two dates — anniversary, project deadline, countdown to vacation, "how long ago did X happen?", or "how far in the future is Y?".
What this tool calculates
- Years + months + days — the human-readable age (e.g. "34 years, 7 months, 12 days")
- Total weeks — useful for milestone tracking ("500 weeks together")
- Total days — for "10,000 days alive" kind of vanity metrics or precise day-counts
- Total hours / minutes — when day-level isn't precise enough
- Weekday — what day of the week the start date fell on
Common use cases
- Calculate exact age — your own, your kid's, a relative's, a pet's
- Datediff online — how many days between two dates for project planning, billing, contracts
- Anniversary calculator — "how long have we been together?" with day-level precision
- Days until deadline — countdown in days/weeks/hours to a future date
- Days since event — "it's been X days since Y" for milestones, memorials, fitness streaks
- Gestational / pregnancy week — input conception date to count weeks/days
Leap years and edge cases
The tool uses actual calendar math — not approximated 365.25-day estimates. Leap years (Feb 29) are counted correctly. Month-end edge cases (Jan 31 + 1 month = Feb 28/29) follow the standard convention of clamping to the last day of the target month.
Privacy
All date math runs in your browser. No date you enter — birthdate or otherwise — is ever uploaded, logged or cached server-side.