Days until a date calculator
Calculate the exact number of days between two dates, for example the days remaining until an event or a deadline.
How it works
Whether it's counting the days until a birthday, a project deadline, or a vacation, this tool converts both dates into a number of days elapsed since a fixed reference, then calculates the exact difference between them, accounting for leap years.
Can the result be negative?
Yes: if the target date is earlier than the starting date, the number of days shown is negative (converted here into an absolute value with the "already passed" message), indicating that the event has already happened rather than being upcoming.
What date format should I use?
Simply use the form's date pickers: they automatically guarantee the YYYY-MM-DD format expected by the calculation, with no risk of entry errors.
100% local processing: the calculation runs entirely in your browser via WebAssembly — no data is sent to a server.