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.
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.
How it works
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
When to use this tool
This tool is designed for quick, practical tasks such as everyday calculations, data formatting, or simple conversions. It is best used when you need fast results without installing software or using complex tools.
When to use
- Quick checks or one-time calculations
- Validating or converting data before using it elsewhere
- Simple tasks that do not require advanced software
When not to use
- Critical financial, legal, or medical decisions
- Large-scale or automated processing
- Situations requiring guaranteed precision beyond basic validation
Always review results before using them in important contexts.
About this tool
This tool helps you perform quick utility operations directly in your browser. It runs entirely in your browser without sending data to a server.
You can use this tool when handling simple tasks without installing additional software. The results should be interpreted as a processed output based on your input data.
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.