Departure Time Calculator
Find out what time to leave so you arrive on time.
Departure time calculator
Travel time
Extra buffer
Leave at
Enter an arrival time to calculate when to leave.
20:23
- Arrive by
- 20:43
- Travel time
- 20 minutes
- Buffer
- No extra buffer
How it works
Start with the time you need to arrive, subtract the travel time, then subtract any extra buffer you want. The result is the time you should leave.
- Arrival time:
- 20:43
- Travel time:
- 20 minutes
- Buffer:
- 0 minutes
- Leave at:
- 20:23
Questions
How do I calculate what time I should leave?
Enter the time you need to arrive, then the travel time. The calculator subtracts that duration, plus any extra buffer, to show when you should leave.
What is the extra buffer for?
Buffer is optional extra time you want before you must arrive. A 10-minute buffer means you leave 10 minutes earlier. Leave it at zero if you do not want extra time.
Can I use AM/PM instead of 24-hour time?
Yes. Choose AM/PM in Time format. Switching formats keeps the same underlying time: 20:43 becomes 8:43 PM, and switching back returns 20:43.
What happens if my departure time is on the previous day?
If travel time plus buffer crosses midnight, the result shows the clock time and a previous-day label, so you do not have to infer it from the clock alone.
Can travel time be longer than one hour?
Yes. Enter hours and minutes. Minutes may go past 59; 80 minutes is treated as 1 hour 20 minutes. Durations longer than a day are allowed and show how many days earlier you should leave.
Can I use this for school pickups, appointments, airports, or meetings?
Yes. It works for any time you need to arrive, as long as you know how long the journey takes. It does not look up a specific place or event type.
Does this calculator account for traffic?
No. This version uses the travel time you enter. It does not predict traffic or calculate a route.
Does the calculator know my location?
No. It does not use your location, maps, or GPS. All it needs is the arrival time and durations you type.