Days Until a Date counts forward from today to any date you choose, giving a straight day count rather than leaving you to tally weeks and leftover days on a calendar. It's the tool behind countdowns — to a birthday, a wedding, a trip, an exam, a public holiday, or a deadline that's easier to plan around once it's a single number instead of a date sitting weeks away.
The count is measured from today, and updates automatically the next time you visit, since it always works from the current date on your device rather than a fixed reference point. Leap years are handled automatically as part of the day count, so a countdown that spans 29 February in a leap year is neither over nor under by a day.
It's a genuinely simple calculation, but a useful one to have done correctly and instantly rather than worked out by hand — particularly for dates far enough away that counting weeks on a calendar becomes error-prone.