Add/Subtract Days Calculator
Add or subtract a number of days from a start date. Optionally count business days by excluding selected weekend days and holidays.
Add/Subtract Days Calculator tool
Use a positive number to add days, negative to subtract days.
Business days skip selected weekend days and optional holidays.
Privacy: runs locally in your browser. No inputs are stored or transmitted.
Calendar-day mode adds/subtracts N days directly. Business-day mode moves day-by-day, counting only days that are not marked as weekend days and not listed as holidays. The start date itself is not counted—adding 1 returns the next counted day.
Examples
- Start 2026-03-01, +10 calendar days → 2026-03-11
- Start 2026-03-06 (Fri), +1 business day with Sat/Sun weekends → 2026-03-09 (Mon)
- Start 2026-03-03, -5 business days → date 5 business days earlier
FAQ
- What does this calculator do?
It adds or subtracts a number of days from a start date. You can count either calendar days or business days (excluding selected weekend days and optional holidays).
- What are business days here?
By default, business days are Monday–Friday (Sat/Sun excluded). You can customize which weekdays count as weekends and provide a holiday list to exclude.
- Is the start date included in the count?
No. The calculator moves forward/backward by N counted days starting from the next/previous day. For example, adding 1 day returns the next counted day.
- How do I enter holidays?
Paste dates in YYYY-MM-DD format (one per line or comma-separated). Holidays that fall on an otherwise counted day are excluded when business-day mode is enabled.
- Is any data stored?
No. Everything runs locally in your browser. Inputs are not stored or transmitted.