Calculator
Calendar
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Start: — |
Shift: — |
Total steps counted: 0
Example data
Sample scenarios demonstrating calendar and business day shifts.
| # | Start date | Shift | Mode | Result date | Weekday |
|---|
Formula used
Calendar days: result = start_date + N days using proleptic Gregorian arithmetic. If N is negative the iterator moves backward one day per step.
Business days: iterate one step at a time changing the cursor by +1 or −1 day while skipping Saturdays Sundays and any date found in the provided holiday set until |steps| = |N|.
All computations are anchored in UTC to avoid daylight saving anomalies; the display is formatted in the selected timezone with Intl.DateTimeFormat.
How to use
- Enter a start date.
- Type an integer for days to add or subtract.
- Choose counting mode and optionally list holidays.
- Select your preferred timezone for the formatted output.
- Press Calculate to see the result date and weekday.
- Use Download CSV to export the current result row.
- Use Download PDF to open the print dialog and save as PDF.
Tip: business mode is ideal for schedules contracts and SLAs where weekends are not counted.
FAQs
No. The arithmetic counts days from midnight UTC to avoid daylight saving drift. Timezone only formats the displayed start and result.
When business days mode is chosen each step skips dates listed in the holidays box treating them like weekends.
Yes. Enter a negative number to move backward. Business mode still skips weekends and provided holidays while stepping backward.
Some tools count partial days or apply local midnights. This calculator uses whole-day steps from UTC to keep behavior consistent.
Use the example table as a template. Edit rows then press Download CSV after running examples to export the table.
List any additional non working dates in the holidays box. The algorithm will skip them in business mode.
Typical browsers handle ranges spanning thousands of days. Extremely large values may feel slow in business mode because each step is iterated with skips.