Date Calculator
Compare two dates, add or subtract a duration, or count down to a future date.
This is a practical tool for planning deadlines, travel, anniversaries, and any date-based schedule.
Result
--
Run the calculation to see the date result.
| Metric | Value |
|---|---|
| Years | -- |
| Months | -- |
| Weeks | -- |
| Days | -- |
| Total days | -- |
| Resulting date | -- |
Quick Answer
The date calculator can do three jobs: show the difference between two dates, add or subtract a duration from a start date, and count down to a future date from today.
How to Use It
- Choose a mode.
- Enter the start and end dates or the duration you want to add.
- Click Calculate.
- Read the result in years, months, weeks, days, and total days.
Formula
Date difference = end date - start date
Add or subtract = start date +/- duration
Worked Examples
Example 1: March 1 to March 31 is 30 days apart.
Example 2: Adding 6 months to January 15 gives a date in July.
Example 3: Countdown mode can show how many days remain until a deadline or birthday.
How to Interpret Your Results
| Output | Meaning | Action |
|---|---|---|
| Difference | The amount of time between two dates. | Use it for timelines and durations. |
| Adjusted date | The new date after adding or subtracting time. | Useful for planning deadlines and reminders. |
| Countdown | The time left until the target date. | Use it as a countdown to a future event. |
Frequently Asked Questions
Yes. Pick subtract and choose months as the unit.
Yes. The date math uses the calendar, so leap years and month lengths are handled automatically.
Countdown uses today as the start date by default, while difference mode lets you compare any two dates.
Related Calculators
References
- OmniCalculator reference page
- The calculator supports date differences, date adjustments, and countdowns to future dates.
- Last reviewed: March 2026.