Date Calculator: Days Between Dates
Measure the time between two calendar dates. Your work stays on this device whenever possible.
How to use Date Calculator: Days Between Dates
- Select a Calculation Mode: "Difference Between Two Dates", "Add Duration to Start Date" or "Subtract Duration from Start Date".
- Set Start date and End date; in the add and subtract modes fill Years, Months, Weeks and Days to add/sub instead.
- Pick which days are weekends in Weekend Days, for example "Friday & Saturday (Middle East)" or "No weekends (7-day workweek)".
- List public holidays as YYYY-MM-DD values separated by commas in Excluded Holidays, and tick "Include end date (+1 day)" if both endpoints count.
- Press "Calculate" to see calendar days, business days, weekend days, weeks, hours, minutes and seconds.
Worked example
Use Difference mode with Start 2025-01-06, End 2025-01-31, Saturday & Sunday weekends, Excluded Holidays 2025-01-20, and the end date not included. That gives 0 years, 0 months, 25 days: 6 weekend days (11, 12, 18, 19, 25, 26), 1 holiday and 18 business days, or 3 weeks and 4 days, and 600 total hours.
When to use this tool
- Counting working days between a contract start and a delivery deadline, minus known holidays.
- Finding the date that falls 90 days after an invoice was issued.
- Working out a workweek in a country where the weekend is Friday and Saturday.
Important limitations
Standard business days calculations exclude Saturday and Sunday. Custom regional weekend configurations (e.g. Friday/Saturday) and statutory holidays can be custom-entered as comma-separated dates.
Frequently asked questions
What does the business-day count exclude?
It skips the weekend days you selected and any listed holidays. A holiday that falls on a weekend is counted as a weekend day, not as a holiday, so the holiday total can be lower than the list you typed.
What happens if the end date is before the start date?
The tool swaps them and notes that the end date was earlier, so you still get a positive span. Nothing is reported as negative, which is worth remembering when the direction matters.
When do I need the include-end-date option?
Use it when both endpoints count, such as a hotel stay that includes the last night or a leave request. Without it the span is the plain difference, so 1 to 2 January is one day.
How does adding months behave near month ends?
Years and months are added first using calendar arithmetic, then weeks and days. Starting on 31 January and adding one month can roll into early March because February is shorter.
Are time zones or clock changes considered?
No. Every calculation uses UTC calendar days, so daylight-saving changes do not affect the day count. The hour, minute and second totals are just days multiplied by 24, 60 and 60.