Find the difference between two dates, or add/subtract days, weeks, months and years from any starting date. Includes weekday output and total-day summary.
Advertisement
How it works
Difference calculation walks the calendar to accurately handle month-length variations and leap years. Add/subtract uses the built-in Date object with normalization to avoid overflow.
Key features
- Two-tab UI: Difference / Add-Subtract
- Support for days, weeks, months, years
- Total-day summary
- Result includes weekday name
Common use cases
Contract terms
What's the date 90 business days from today?
Project planning
Milestones spaced 6 weeks apart.
Life anniversaries
What date is your 10,000th day alive?
Advertisement
Pro tips
- ◆For business-days-only calculations, use the Business Days Calculator instead.
Common mistakes to avoid
- ✕Adding "1 month" and expecting the same day-of-month in short months (e.g. Jan 31 + 1 month is not Feb 31, so it rolls to March 3rd).
Frequently asked questions
Does it handle leap years?▼
Yes, correctly for both difference and add/subtract calculations.
Advertisement