What Time Should I Leave?
Enter when you need to arrive and how long the trip takes — get an exact leave-by time with optional buffer and a leave-now check.
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How it works
Enter your arrival time and travel duration. We subtract travel and optional buffer to show exactly when to leave — plus a leave-now check against the current clock.
Informational only — not professional advice. Report an error.
What time should I leave to arrive at 8:00 AM?
Subtract your travel time and any buffer from your arrival time. If you need to be somewhere at 8:00 AM and the drive takes 40 minutes with a 5-minute buffer for parking, leave at 7:15 AM. The calculator above does that math instantly — change the arrival time to match your appointment, flight, or shift start.
What time should I leave if my drive takes 45 minutes?
Enter your must-arrive time and set travel to 45 minutes. For a 9:00 AM meeting, a 45-minute commute with no buffer means leaving at 8:15 AM. Add 5–10 minutes of buffer if you need gas, traffic wiggle room, or walking from a parking garage — rush-hour traffic is not built in; pad travel time when roads are unpredictable.
How do I calculate what time to leave?
Use this formula: leave time = arrival time − travel time − buffer time. Work backward from when you must be there, not forward from when you want to leave. Tap Check if I should leave now to compare the result to the current clock — handy when you are getting ready and wondering if you are already late.
Running late is stressful when the meeting, flight, or school bell will not wait. Most people guess a departure time by rounding travel minutes in their head — then forget parking, a slow elevator, or one red light that eats five minutes. Working backward from when you must arrive is the reliable way to leave on time, and it takes only addition in reverse: subtract every minute you will spend getting there from your deadline.
This calculator asks for three things: the time you need to be there, how long the trip takes (drive, transit, walk, or all of the above), and optional buffer minutes for surprises. The formula is leave time equals arrival time minus travel time minus buffer. A 9:00 AM appointment with a 45-minute commute and a 10-minute buffer means leaving at 8:05 AM — not 8:15, which would put you at the door exactly on time with zero margin.
Buffer time is the difference between on paper and real life. Five minutes covers finding a parking spot; ten to fifteen minutes helps for airport curbside drop-off, school security lines, or a coffee stop. Rush-hour traffic is not modeled automatically — if your navigation app says 35 minutes at 7 AM but 55 minutes at 8 AM, enter the worse number or add buffer instead of hoping traffic cooperates.
The leave-now check compares your calculated departure to the current clock. Enable it when you are getting dressed or finishing breakfast and wondering whether you are already late. If the leave-by time has passed, the result switches to Leave now so you can stop recalculating and start moving. It uses your device local time — handy for same-day trips, less relevant if you are planning tomorrow schedule tonight.
Common scenarios: work starts at 8:00 with a 40-minute drive — leave at 7:20 with no buffer, or 7:15 with five minutes for the garage. Doctor appointment at 2:30 PM downtown with 25 minutes transit plus 10 minutes to find the suite — leave at 1:55. Flight boarding at 6:00 AM with a 50-minute drive and 90 minutes for check-in and security — back up to a 3:40 AM departure unless you are checking bags curbside with PreCheck.
Pair this with the Fuel Cost Calculator for road-trip budgeting, the Trip Budget Calculator for vacation planning, or the Timezone Converter when your arrival is in another zone. For recurring commutes, note the leave-by time that worked twice and reuse it — consistency beats perfect math on sleepy mornings.
Quick tips
- Work backward from arrival — never forward from when you feel like leaving.
- Add 5–15 minutes of buffer for parking, lines, or traffic variance.
- Use the leave-now check when you are ready to walk out the door.
- Pad travel time on rainy days, school mornings, and holiday weekends.
- Save a screenshot of the leave-by time for recurring appointments.
Planning a longer trip? Pair with the Trip Budget Calculator or Fuel Cost Calculator.