D-day calculator
Count days left or days since
Pick a date to see the days left or the days since.
Dates are calculated on this device only and never saved.
How to use
- Under Calculation type, choose D-day / Days since or N days from.
- Check the Base date. It starts as today; if you change it, press Today to go back.
- For D-day / Days since, pick a target date or start date. For N days from, enter the number of days and choose After or Before, or pick one under Common numbers.
- Turn on “Count the first day as day 1” when the first day should count, as in “100 days together.”
FAQ
How many days have we been together?
Choose D-day / Days since, keep the Base date as today, enter the day you met, and turn on “Count the first day as day 1.” The result shows as Day 100 and so on, and if you met today it’s Day 1. The same works for a start date at work or a baby’s birthday.
How many days are left until a date?
Keep the Base date as today and pick the future date. You’ll see a label like D-30 with “30 days to go.” On the day itself it shows D-Day, and after that it counts up as D+1, D+2, and so on.
What date is our 100th day?
Choose N days from, set the Base date to the day you met, enter 100, and keep the direction as After. With “Count the first day as day 1” on, the result is 99 days later, which is day 100. With it off, you get the date exactly 100 days later.
Why is “Day N” one more than “days ago”?
“Days ago” is the gap between the two dates, while “Day N” counts the first day as day 1. If you met yesterday, that was 1 day ago and today is Day 2. With the option on, both are shown.
Can time zones or daylight saving time throw the count off by a day?
No. Days are counted from calendar dates alone, without times, so DST changes don’t affect the result. “Today” follows the date on this device.
What range of dates is supported?
Any date from January 1 of year 1 to December 31, 9999. In N days from mode, the number of days must be a whole number of 1 or more.