Age & Date Difference Calculator

Enter a date of birth or any start date, and optionally change the second date if you want the difference to a date other than today. The calculator returns the exact gap in years, months and days, taking leap years and differing month lengths into account rather than approximating with a fixed 365-day year.

The totals panel restates the same span in months, weeks, days, hours and minutes, which is handy for anniversaries, project timelines, visa and probation periods. You also get the weekday the start date fell on and a countdown to the next anniversary, so you can see at a glance how long until the date comes around again.