Find date differences and perform forward or backward calendar offsets accurately.
Overview
The Date Calculator solves two common tasks: counting time between two dates and finding a future or past date from an offset.
It is useful for project planning, contracts, deadlines, travel windows, and recurring event schedules.
Business-day adjustments may be required for contracts and payroll; this tool counts calendar days unless you exclude weekends manually.
Steps
Select date difference or date add/subtract mode.
Provide the initial reference date.
Use an end date or specify days, weeks, months, and years.
Compute exact date span or resulting date.
Check resulting day of week for scheduling decisions.
Math
Date difference = end date - start date; Result date = start date +/- offset
The calculator uses calendar arithmetic, respecting month lengths and leap years when shifting dates or counting intervals.
Worked cases
E - S
152 days
S + 45 days
2026-07-17
S - 3 calendar months
2026-03-02
Why use this
Questions