Clarity9 FREE TOOLS
Date & time, made clearer.
Count calendar days, compare ages, and separate weekdays from weekends.
Tools in this category
Date Addition Calculator
Add or subtract whole calendar days from a date and find the resulting weekday.
Time Duration Calculator
Find elapsed wall-clock hours and minutes between two times, including an overnight interval.
Age Calculator
Find completed years of age and total elapsed calendar days between two dates.
Date Difference Calculator
Count the days and full weeks between two calendar dates.
Business Days Calculator
Count Monday-to-Friday weekdays between two dates, excluding the end date.
Day of Year Calculator
Find a calendar date’s ordinal day number and the days remaining in its year.
Leap Year Calculator
Check whether a Gregorian calendar year contains February 29 and 366 days.
ISO Week Number Calculator
Find the ISO week number, week-year and Monday-through-Sunday range for a date.
Work Hours Calculator
Calculate net shift hours after an unpaid break, including shifts that end the next day.
Choosing the right date & time tool
Our date tools use calendar dates rather than local clock times, so daylight saving changes do not add or subtract a day. Date ranges include the start and exclude the end unless stated otherwise.