Date Add / Subtract Calculator
Add or subtract days, weeks, months, or years from any date. Get the target date, weekday, day of year, ISO week, and Unix timestamp in one calendar-date calculator.
Choose a base date and offset to calculate the target calendar date.
How to Use This Tool
- Pick the starting date you want to move forward from or backward from.
- Enter how many days, weeks, months, or years to add or subtract.
- Review the target date, weekday, day of year, ISO week, and Unix timestamp.
What This Page Answers
- What date is 100 days from today?
- What happens when I add 12 weeks to a date?
- How do month and year offsets handle shorter months?
- What is the resulting Unix timestamp and ISO week?
Frequently Asked Questions
Select your base date, enter 100, keep the unit on days, and choose add to get the target calendar date instantly.
This tool moves by calendar days, weeks, months, and years. It does not skip weekends. Use the business days calculator when you only want weekday-based results.
Month and year offsets are clamped to the last valid day of the target month when needed, which avoids invalid dates such as February 30.
Yes. Alongside the resulting calendar date, the tool also shows the UTC Unix timestamp, day of year, and ISO week number.