How to use the Date Add or Subtract Calculator
Enter the starting date and number of days and the result appears straight away. Everything runs in your browser, so nothing you type is uploaded.
The formula
Result = start date ± whole calendar days.
Examples
- 30 days after 1 January 2026
Resulting date: 2026-01-31
- 90 days after 15 March 2026
Resulting date: 2026-06-13
- 45 days before 1 June 2026
Resulting date: 2026-04-17
Limitations and assumptions
Results are estimates for general information. Check assumptions and inputs before relying on them.
Frequently asked questions
How do I add days to a date?
Enter the date and number of days and choose add. Month and year boundaries are handled automatically.
Does it skip weekends?
No, it counts calendar days. Use the next business day calculator for working days.
Does it handle leap years?
Yes, 29 February is included when it exists.
How many days are between two dates?
Use the date difference calculator.