Date Calculator
Whether you’re counting days between events or shifting deadlines by business days, this calculator handles every date math scenario.
Date Range Summary
Start
Sunday, March 29, 2026
End
Sunday, March 29, 2026
Business days: 0
Weekend days: 1
Approx months: 0.03
Approx years: 0.00
Instructions
Choose your mode
Pick “Count Days” to find the duration between two dates, or “Add/Subtract” to shift a single date by days.
Enter relevant dates
For durations, specify start and end. For shifting, select the base date and days to move. Toggle “business days” to skip weekends automatically.
Review results
See total days, business days, and approximate weeks/months (duration) or the resulting date with weekend adjustments (add/subtract).
Formula
Total Days = (End − Start) + 1
Business Days = Count of weekdays between Start and End
Approx Months = Total Days ÷ 30.4375
Example: Adding 30 business days to 2025-11-09 yields simply 30 calendar days ahead depending on the setting.
Why Date Math Matters
Accurate date calculations keep projects on track, prevent missed deadlines, and help coordinate across teams and time zones.
- Plan contract milestones or invoice due dates without manually counting days.
- Calculate retention periods, warranties, or compliance dates with precision.
- Schedule events and marketing campaigns by aligning to business days.
- Avoid errors caused by leap years, month lengths, or weekend overlaps.
Common Questions
Does this include holidays?
Holidays aren’t excluded automatically. Pair with the Business Days Calculator to subtract specific holiday dates.
Are start and end dates inclusive?
Yes. If you need exclusive ranges, subtract one day from the total or adjust the inputs accordingly.
What about time zones?
Dates operate in local time regardless of time zones. For cross-country projects, ensure both parties use the same reference date.
Can I shift by months instead of days?
This calculator focuses on days. For month-based shifts, run multiple adjustments or use the Calendar Calculator to preview months.
Calculate Between Any Two Dates
The Date Calculator computes the exact number of days, weeks, months, and years between any two dates. It also lets you add or subtract days from a known date to find a future or past date.
This is invaluable for project planning, calculating due dates, determining elapsed time for contracts, figuring out how many weekdays remain before a deadline, or finding the exact number of business days between two dates.
The calculator supports date operations across centuries and accounts for leap years automatically. It also shows the day of the week for any given date and can calculate the number of weekdays and weekend days in a range.
Frequently Asked Questions
Does it account for leap years?
Yes, the calculator automatically factors in leap years when computing the difference between dates.
Can I find business days only?
Yes, you can toggle the calculation to count only business days (Monday through Friday), excluding weekends.