The formula
Gate Time works backward from the boarding time you enter. Every step below is added up and subtracted from boarding to produce your leave-by time:
Leave by = Boarding time − (gate + security + bags + check-in + parking + drive + your buffer)
| Be at the gate before boarding | 15 min |
| Security — TSA PreCheck / Global Entry | 15 min domestic / 20 min intl |
| Security — standard lane | 30 min domestic / 45 min intl |
| Checked bag drop | +20 min |
| International check-in / customs | +30 min |
| Parking — curbside drop-off | +0 min |
| Parking — short-term (park & walk) | +10 min |
| Parking — long-term (park + shuttle) | +25 min |
| Drive to the airport | your input, or an estimate |
| Personal buffer | your choice — presets below |
Why these numbers
- Gate (15 min): airlines close the boarding door before departure — this margin keeps you from being the last call.
- Security: reflects typical screening plus line time. International lanes and farther terminals run longer, so international flights get more time; PreCheck/Global Entry cuts it down.
- Checked bags (+20 min): bag-drop counters have their own line and a cutoff well before departure.
- International (+30 min): document checks, longer counters, and immigration/customs add real time.
- Parking: drop-off adds nothing; short-term means a walk; long-term usually means waiting on and riding a shuttle.
- Buffer: pure personal cushion. Presets: Relaxed adds 30 min (warns at 60 min left), Normal adds 10 min (warns at 30), Efficient adds none (warns at 15) — all fully adjustable.
These are conservative planning estimates, not guarantees. Conditions vary by airport, day, and TSA wait times — when in doubt, add buffer.
The drive-time estimate
When you pick a departure airport, tap "use my nearest airport," or hit Calculate with an airport set, and road routing is configured, Gate Time asks OpenRouteService for the real road distance and drive time — for that lookup your coordinates are sent to OpenRouteService. If routing isn't configured, or the request fails, Gate Time falls back to the straight-line (great-circle) distance at roughly 35 mph plus a 5-minute base, computed entirely in the browser.
The automatic "nearest airport" detection on page load is always the local straight-line estimate and contacts no one. Either way, the drive-time field is fully editable — adjust it to match your actual drive. Distance can be shown in miles or kilometers.
The urgency bar
The colored countdown bar fills over a fixed 4-hour (240-minute) window as your leave-by time approaches, and your warning threshold sets when the red "leave soon" alert appears. Neither changes the leave-by time itself — they're just visual pacing.
The data
The airport list comes from OurAirports, a public-domain dataset. Gate Time keeps every airport that has both a 3-letter IATA code and coordinates, since both are needed for lookup and the distance math.
- Code lookup searches the full airport list.
- "Find nearest airport" only considers airports with scheduled commercial service, so GPS points you to somewhere you'd actually fly from — not the closest private airstrip or heliport.
- Coordinates are each airport's reference point; an explicit lookup uses them for real road routing via OpenRouteService when configured, otherwise for a straight-line distance converted to a rough drive time.
The dataset is refreshed manually. Spot something off? It's an estimate — adjust any field in the calculator to match your reality.