D-day counter
Date
Result
Today counts as day 0, so tomorrow reads D-1. Dates that have passed show as D+.
Kept dates
You can keep up to 10.
What this counter does
It counts the days between the date you enter and today. A date still ahead shows as D-N, today shows as D-DAY, and a date that has passed shows as D+N. The weekday and the same figure in weeks come with it.
How the days are counted
Today is day 0. So if the date is tomorrow it reads D-1, and if it is today it reads D-DAY. If you need the "counting today as the first day" version, add 1 to the number here. Rules differ from place to place, which is why this page states its own.
Can I use a date in the past
Yes. Past dates are not blocked — they count up as D+N. "How long has it been" is a real use, so cutting it off would remove half the tool.
Where are kept dates stored
In this browser only (localStorage). Nothing is sent to a server and there is no account. They will not appear on another device, and clearing browser data removes them. You can keep up to 10.
When does the day roll over
At midnight on this device. If the "counted from" date is not today, reload the page.
How is the share link built
Share builds a link that carries the values you entered. Opening it fills the same fields and shows the result right away, so the person you sent it to does not have to type anything. The values are plain to see in the address, so editing the link by hand is fine too — anything out of range simply opens the empty calculator.