A days-until calculator (also called a countdown calculator) tells you how much time is left until a future event — a deadline, a holiday, a birthday, a launch, a vacation. The most-searched variants are “days until Christmas”, “days until New Year”, and “days until [arbitrary date]”, but the same calculation applies to any target. This tool ticks down by the second, expressing the remaining time in two complementary ways: as a single integer (days, weeks, total hours) for spreadsheet-style planning, and as a calendar breakdown (years, months, and days) for human-readable phrasing. You can label the event, copy a shareable link that re-opens the same countdown, or jump to popular targets with the quick-pick chips. Pair it with the Day of Week Calculator to find what weekday your target lands on, or the Age Calculator for a live next-birthday countdown.