Date & Time

Browser-first date and time calculators for calendars, countdowns, and durations.

Add Time
Add days, hours, minutes, and seconds to a date/time.
Age Calculator
Calculate age in years, months, and days from a birth date.
Anniversary Calculator
Find the next anniversary date and days until it.
Business Days Calculator
Count business days (Mon–Fri) between dates with optional holidays.
Countdown Timer
Live countdown to a target date and time in your browser.
Days Between Dates
Count calendar days between two dates in your browser.
Elapsed Time Calculator
Measure forward elapsed time between two date/times in your browser.
Pregnancy Due Date Calculator
Estimate a due date from LMP or conception using a Naegele-style rule.
Retirement Calculator
Count calendar time until a retirement date or target age.
School Days Calculator
Count school days (Mon–Fri) between dates, excluding breaks.
Subtract Time
Subtract days, hours, minutes, and seconds from a date/time.
Time Difference Calculator
Compute the difference between two date/times as days, hours, minutes, and seconds.
Time Duration Calculator
Compose or expand durations between total seconds and days/hours/minutes/seconds.
Working Days Calculator
Count Mon–Fri working days between two dates, with optional holidays.