Date Calculation & Calendar Guides

Explore our comprehensive educational guides on date mathematics, calendar counting conventions, statutory deadlines, and business day calculations.

Calculate the exact calendar difference, full weeks, and days between any two dates with inclusive options.

See how many days, weeks, and milestones have passed since a birthday, anniversary, or historical event.

Count down the exact days and weeks remaining until an upcoming vacation, deadline, or special occasion.

Count working days between dates while excluding weekends and official US federal holidays.

Add or subtract any number of calendar or business days to find the exact target future or past date.

Find what day number of the year it is today out of 365 (or 366), remaining days, and quarter progress.