Date & Time
Exact Age, Date Differences, Business Days & Event Countdowns. All computations happen instantly in your browser with zero latency and zero data transmitted to servers.
Age Calculator
Calculate exact chronological age in years, months, days, hours, and next birthday.
Date Difference Calculator
Calculate exact elapsed days, weeks, and months between two dates.
Working & Business Days Calculator
Calculate working business days between two dates, excluding weekends.
Days From Today Calculator
Find the future or past calendar date N days from today.
Time Difference (Duration) Calculator
Calculate elapsed duration between two clock times in hours and minutes.
Event Countdown Calculator
Countdown remaining days and hours to an upcoming target date.
ISO Week Number Calculator
Determine the ISO-8601 calendar week number for any date.
Leap Year Checker
Determine whether a calendar year is a leap year (366 days) under Gregorian calendar rules.
Day of the Week Calculator
Find the day of the week (Monday through Sunday) for any historical or future date.
Date Add & Subtract Calculator
Add or subtract days from a base date to find deadlines or past milestones.
Calendar Interval & Milestone Calculator
Calculate precise elapsed calendar intervals, quarterly project milestones, and target delivery dates.
Date Differences, Business Days & Chronological Math
Calendar and time arithmetic can be tricky due to varying month lengths, leap years, and weekend schedules. These tools calculate exact durations, countdowns, and working business days in seconds.
What You Can Calculate in This Hub
Popular Problem-Solving Workflows
- •A leap year occurs every 4 years, except for end-of-century years that are not divisible by 400 (e.g. 2000 was a leap year, but 1900 was not).
- •Always clarify whether date intervals are inclusive or exclusive of the starting day.
Thirty days has September, April, June, and November! All the rest have thirty-one, save February alone.
How Date and Time Differences Are Calculated: Chronological Math & Workdays
An exploration of Gregorian calendar arithmetic, UTC epochs, leap second handling, and working day calculation algorithms.