Departure Time Calculator
Calculate the recommended departure date and time to reach a target arrival, including overnight and multi-day journeys.
How Departure Time Is Calculated
Enter the date and time you need to arrive by, along with your total travel duration in hours and minutes. The calculator subtracts that duration from your arrival moment to find your recommended departure date and time — correctly handling journeys that run overnight or span multiple days.
Departure Time vs. Arrival Time
This calculator works backward from a target arrival time and a known duration to find a departure time. The Arrival Time Calculator works the other direction: given a departure time and a duration, it tells you when you'll arrive. Use whichever one matches the information you already have.
FAQ
How is the recommended departure time calculated?
The calculator combines your arrival date and time into a single moment, then subtracts your travel duration (in hours and minutes) from it. The result is your departure moment, split back out into a recommended departure date and time.
Can this calculator handle overnight journeys?
Yes. If subtracting the travel duration carries the departure back past midnight, the recommended departure date automatically rolls back to the previous day.
Can this calculator handle multi-day journeys?
Yes. There's no cap on the duration you can enter — a duration of 51 hours, for example, correctly lands the recommended departure two full days before your arrival date.
Do I need to account for time zones?
This calculator uses the date and time you enter as-is and does not convert between time zones. If your journey crosses time zones, enter your desired arrival time in the arrival time zone and adjust the recommended departure yourself if you need it in a different zone.
When should I use this instead of the Arrival Time Calculator?
The two calculators run in opposite directions. Use the Arrival Time Calculator when you know your departure time and want to find your arrival time. Use this calculator when it's the other way around — you know when you need to arrive and want to find out when to leave.