How it works
Add / Subtract Days is designed to give you the result immediately. The calculation or processing happens on your device for this tool, so normal use does not require an account or a file upload.
Privacy
This tool is marked offline-capable. Your inputs are used in the current browser/app session and are not required to be sent to Wiunix Tools to perform the operation.
Add or subtract calendar days without time-zone drift
Enter a date and a positive or negative number of days. The calculation uses calendar-day arithmetic instead of elapsed local hours, avoiding DST-related one-hour surprises.
- Positive or negative day offsets
- Calendar-day arithmetic
- Month/year rollover
- DST-safe date math