Before guides

Clear explanations that support the before calculator.

How to subtract time from a date

Find an earlier date by removing a duration from a known starting point.

Calculate the exact clock time a number of hours before another time.

Find the calendar date a specified number of days before another date.

Move backward by complete seven-day periods.

Count backward while excluding weekends and applicable holidays.

Understand the difference between a relation to an event and a relation to now.

Keep date subtraction correct when locations use different offsets.

Turn a final deadline into earlier milestones and start dates.