Enter your departing flight and where you're setting off from. It works backwards through security and bag drop to tell you when to walk out the door — with time to spare, not a sprint.
Leaving for a departing flight is the same puzzle as a pickup, run backwards. You have a fixed deadline — the moment you need to be inside the terminal — and everything before it is drive time you cannot control. Leave By takes your flight number and where you're setting off from, and tells you the exact minute to walk out of the door.
The calculation is built from four things: your flight's departure time (live, and it follows delays), the time you need at the airport for bag drop, security and the walk to the gate, your drive with traffic, and a small get-ready cushion. Each is adjustable. Once you're on the road, the live "I'm driving" mode re-routes from your GPS and tells you whether you're still ahead of your deadline.
This is the number everyone guesses at, and the one that decides whether the trip is calm or a sprint. Measured from walking through the terminal door to sitting at the gate:
Leave By defaults to 2 hours and switches preset automatically when it can tell your flight is international. If you have lounge access, priority security, or you are flying from a small regional airport, dial it down — the slider is there to be moved.
Airlines close things in stages, and every one of them lands before the time printed on your boarding pass:
Set your airport allowance so that it clears the earliest of these deadlines with room to spare, not so that it merely gets you there by departure time.
Collecting someone instead? The arrivals pickup timer works forwards from the landing time through baggage reclaim.
Work backwards from your departure time. Allow about 60 minutes at the airport for a domestic flight with hand luggage, 90 with checked bags, and 2 hours for an international flight — then add your drive time and a cushion for getting out of the door. Leave By does that arithmetic for you using live drive times and your flight's actual departure time.
Most airlines advise 2 hours before a domestic flight and 3 before an international one, which builds in their own margin. In practice 60–90 minutes is comfortable for a domestic trip with no bags to drop, while a busy international hub at peak deserves the full 3 hours. Leave By defaults to 2 hours and detects whether your flight is international.
Bag drop typically closes 45–60 minutes before departure for international flights and 30–45 for domestic, and the gate usually closes 15–25 minutes before departure. These are the real deadlines — not the departure time itself — so leave enough margin that a slow security queue does not cost you the flight.
Yes. With live traffic enabled it uses real-time driving times; otherwise it applies an adjustable traffic allowance on top of the free-flowing drive estimate.
Yes. Leave By tracks the live departure time and re-checks it periodically, so if your flight slips the leave-by time moves with it. Never rely on a delay staying put, though — airlines can pull a delayed departure forward.
No. Leave By is free and needs no sign-up. It runs in your browser and can be installed as an app for one-tap access.