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➕➖ Date Math
Add or subtract years, months, days, hours, and minutes from a date. Quick online date calculator.
Date Math Calculator
Add or subtract years, months, days, hours, or minutes to a base date. Useful for deadlines, scheduling, or quick date calculations.
How to use this tool
- Pick the base date and time. The field defaults to your current local time to get you started instantly.
- Enter the offsets you want to add or subtract. Use negative values to subtract months, days, or minutes from the base.
- Review the calculated timestamp in ISO 8601, a friendly local format, or Unix epoch seconds, then copy whichever format you need.
Popular use cases
- Calculate project or sprint deadlines without reaching for a calendar.
- Work out renewal dates for subscriptions, warranties, or domain registrations.
- Plan content publishing schedules by shifting posts forward or backward in bulk.
Productivity tips
- Reset the calculator before a new scenario so the base timestamp refreshes to the current moment.
- Toggle between ISO and local formats to paste results into automation scripts or human-friendly docs.
- Combine multiple offsets—such as 1 year and -2 days—to mirror real-world billing or notice periods.
FAQ
- Can I subtract time as well as add it?
- Yes. Enter negative values (for example, -3 days or -45 minutes) to move backward from the base timestamp.
- How are leap years and daylight saving handled?
- Calculations rely on the Luxon date library, which tracks leap years and daylight saving rules for your locale.
- What happens if I type an invalid date?
- The result cards show em dashes when the base date cannot be parsed. Update the input to a valid ISO date or use the reset button to recover.
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