📅 Date Calculator
D-Day countdown, add or subtract days from a date, and calculate the difference between two dates. Share results via URL.
🎯 D-Day Countdown
How to Use the Date Calculator
This date calculator offers three powerful modes for all your date-related needs. Whether you're counting down to a deadline, figuring out a future date, or measuring the time between two events, it has you covered.
3 Calculation Modes
🎯 D-Day Countdown
Set a target date and see how many days remain. Future dates show as D-30 (30 days left), past dates as D+5 (5 days ago), and the target day itself as D-Day. You can change the base date to count from any starting point.
➕ Add / Subtract Days
Pick a starting date and add or subtract a number of days, weeks, months, or years. Perfect for questions like "What date is 90 days from now?" or "What was the date 6 months ago?" The result includes the day of the week.
📏 Date Difference
Enter two dates to find the exact duration between them in days, weeks, months, and years. Great for calculating age, tenure, project duration, and more. A detailed year/month/day breakdown is also provided.
Common Use Cases
- Exam countdown — Set your exam date and track D-Day
- 100-day anniversary — Add 100 days to a relationship start date
- Employment duration — Date difference from hire date to today
- Passport expiry — Countdown to your passport's expiration
- Due date estimation — Add 280 days to the last menstrual period
- Project deadlines — Track days remaining until a milestone
URL Sharing
Click the "Share Link" button below your result to copy a URL that includes your date settings. Send it to friends, colleagues, or bookmark it so you can check your D-Day anytime without re-entering dates.
Frequently Asked Questions
How does the D-Day countdown work?
It subtracts the base date from the target date to get the number of remaining days. D-Day itself is displayed as D-0, and past dates are shown as D+N.
What date is 100 days from today?
Use the "Add / Subtract" mode with base date set to today, direction "Add", unit "Days", and amount 100 to find the exact date and day of the week.
How do I find the days between two dates?
Select the "Date Difference" mode, enter a start and end date, and the calculator will show the total in days, weeks, months, and years.
Can I share my calculation?
Yes! Click "Share Link" to copy a URL with your date settings. Anyone opening the link will see the same calculation.