Date Calculator: Add Days, Weeks & Count Weekdays
Add calendar days or weeks and compare Gregorian dates with explicit weekday-count boundaries, without daylight-saving-hour arithmetic.
Enabling local controls…
1. Set date calculation
Calculated in page memory, without upload or storage. Gregorian civil dates are unaffected by DST. No month, year or holiday arithmetic.
2. Result
Enter dates or load a sample, then calculate.
How to use this tool
Enter ISO calendar dates, select day or week arithmetic or an interval, and review the stated endpoint convention for weekday counts.
When not to use it
Dates are not timestamps. No public holidays, business calendars, historical calendar cutovers, month/year arithmetic or legal deadline calculation.
Read the guide →