Age & Date Difference Calculator
Find an exact age or the difference between two dates in years, months, weeks, and days. Calculations happen on your device — nothing is stored or sent anywhere.
How to use this tool
- In Age mode, enter a date of birth — the 'as of' date defaults to today.
- In Date difference mode, enter any two dates.
- Read the exact difference in years, months, and days, plus totals in months, weeks, days, and hours.
How it works
The calculation is calendar-accurate rather than an approximation: it counts whole years first, then whole months, then remaining days, borrowing from the previous month when needed. That's why someone born January 31 turns exactly one month old on the last day of February.
Total days are computed from the actual number of days between the two dates, so leap years are handled correctly.
Frequently asked questions
How is age calculated exactly?
Whole years first, then whole months, then leftover days. For example, from 1990-06-15 to 2026-07-06 is 36 years, 0 months, 21 days.
Does the calculator handle leap years?
Yes. Total-day counts use real calendar dates, so February 29 birthdays and leap-year spans are counted correctly.
What can I use date difference for?
Anything that needs an exact span: tenure at a job, days between invoices, project durations, visa windows, or how long until a deadline.