Duration & day count tool

Days Between Dates Calculator

Count total elapsed calendar days, weekdays, and weekend days between any two dates. Customize boundary inclusion rules, view holiday impacts, and export the complete schedule to CSV.

Configure date range

Pick start/end dates and inclusion rules.

Quick Range Presets

Start date

End date

Include start dateInclude end dateExclude US federal holidays from business days

Total Days

4 days

Calendar span

Business Days

4 days

Working days

Weekends

0 days

Sat & Sun

Holidays

0 days

US Federal

Preview

Check the result before copying or exporting.

4 days

Weekday days: 4
Weekend days: 0
US federal holidays: 0
Business days: 4

First 20 included dates

Preview the full list via CSV export.

Date	Type
2026-05-04	Weekday
2026-05-05	Weekday
2026-05-06	Weekday
2026-05-07	Weekday

Export

Download CSV or share your settings.

How to Calculate the Exact Number of Days Between Two Dates

Determining the duration between two calendar dates is a foundational requirement in project management, billing schedules, lease agreements, and statutory compliance. However, because months vary from 28 to 31 days and workweeks exclude weekends, calculating time intervals manually is prone to human error.

Calendar Quarter & Semi-Annual Day Counts (2026 & 2027)

For fiscal reporting, quarterly targets, and budget planning, here is the official breakdown of elapsed calendar days and standard business days for each quarter in 2026 and 2027:

Quarter	Date Span	Calendar Days	Working Days (2026)	Working Days (2027)
Q1	Jan 1 – Mar 31	90 Days	64 Weekdays (61 Net Federal)	64 Weekdays (61 Net Federal)
Q2	Apr 1 – Jun 30	91 Days	65 Weekdays (63 Net Federal)	65 Weekdays (63 Net Federal)
Q3	Jul 1 – Sep 30	92 Days	66 Weekdays (64 Net Federal)	66 Weekdays (64 Net Federal)
Q4	Oct 1 – Dec 31	92 Days	66 Weekdays (62 Net Federal)	66 Weekdays (61 Net Federal)
Full Year	Jan 1 – Dec 31	365 Days	261 Weekdays (250 Net Federal)	261 Weekdays (249 Net Federal)

Legal & Contractual Notice Periods

When calculating legal notice periods (such as a 30-day lease termination or a 14-day defect notice), statutory rules generally require you to exclude the day of the triggering event. The first full day begins on the following morning, and the deadline expires at the conclusion of the final day.

Human Resources & Benefit Vesting

Employee benefit programs, probationary reviews (typically 90 days), and stock option cliff vesting (1 year = 365 calendar days) depend on precise day counting. Using calendar days ensures full equity compliance regardless of how weekend dates fall.

Does this calculator include weekends in the total days count?

Yes. The total days figure represents elapsed calendar days, which includes Saturdays and Sundays. Below the main total, you will also see a granular breakdown distinguishing business days (weekdays) from weekend days.

Should I include or exclude the start date and end date?

For standard elapsed duration (e.g. 'how many days have passed?'), leave the start date included and end date excluded (End Date minus Start Date). If you are measuring an event duration where both the beginning day and ending day require full-day participation or reservation (such as hotel stays or equipment rentals), enable both checkboxes.

How do 2026 and 2027 leap year rules affect date counting?

Neither 2026 nor 2027 is a leap year (the next leap year is 2028). February in both 2026 and 2027 contains exactly 28 days, giving each of these years precisely 365 calendar days (52 weeks and 1 extra day).

Can I account for US federal holidays when calculating days between dates?

Yes. The business-day breakdown allows you to toggle US federal holiday observation, ensuring that statutory non-working days like Memorial Day, Labor Day, Thanksgiving, and Christmas are excluded from your net working day total.

How are days between dates calculated across time zones?

All calculations operate on standard Gregorian calendar day boundaries (UTC midnight-to-midnight) rather than local epoch timestamps. This prevents errors caused by daylight saving time shifts (23-hour or 25-hour days) or international dateline crossings.

Can I download or print the full date range?

Yes. You can export the entire date sequence between your chosen start and end dates as a formatted CSV file, suitable for import into Excel, Google Sheets, or ERP platforms.