This 120 day calculator counts the days between two dates and is useful for 120-day timelines, notice periods, or tracking a 120-day interval.
Everyday life
120 Day Calculator
Calculate the date 120 days from now or between two dates.
Calculator
About this calculator
Formula notes
Days between = date2 - date1 + include_end_date, where include_end_date can add 1 when the end date counts.
Worked examples
- Example: from January 1, 2026 to May 1, 2026 is 120 days when the end date is excluded.
- A 120-day notice starting March 1, 2026 ends on June 29, 2026 when counting whole days.
How to use it
- Enter the start date and end date.
- Choose whether to include the end date.
- Read the day count.
Frequently asked questions
Does it include both the first and last day?
The tool lets you include the end date. By default it counts the span between dates without adding the end date.
Can I use it for dates before 2026?
Yes. Any calendar date can be entered; the calculation works across months and years.
Limits and interpretation
- Date counting conventions vary by contract and jurisdiction; the tool gives a math result, not legal advice.
- The inclusive end-date option changes the result by one day, so choose it to match your rule.