🧮 The math & why
We work backward from your boarding time. Every step below is
added up and subtracted from boarding to give your leave-by time:
Leave by = Boarding time − (gate + security + bags + check-in + parking + drive + your buffer)
| Be at gate before boarding | 15 min |
| Security — PreCheck | 15 dom / 20 intl |
| Security — standard | 30 dom / 45 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 airport | your input / estimate |
| Personal buffer | your slider |
Why these assumptions
- Gate (15 min): airlines close the boarding door before departure — this keeps you from being the final call.
- Security: reflects typical screening + line waits. International lanes and farther terminals run longer, so intl gets more time; PreCheck cuts it down.
- Checked bags (+20): bag-drop counters have their own lines and a cutoff well before departure.
- International (+30): 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 — bump it up for big hubs, holidays, or peace of mind.
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, we ask OpenRouteService for the real
road distance and drive time to the airport — for that lookup your
coordinates are sent to OpenRouteService. If routing isn’t configured, or the request
fails, we fall back to the straight-line (great-circle) distance at
~35 mph + a 5-minute base, computed entirely in your browser. The
automatic “nearest airport” detection on load is always the local straight-line estimate
and contacts no one. Either way the drive-time field is fully editable — adjust it to your
actual drive. Distance is shown in miles or kilometers per the toggle in “Getting There.”
The urgency bar
The colored bar fills over a fixed 4-hour (240-min) window as your leave-by time
approaches, and your warning threshold sets when the red “leave soon” alert appears.
Neither changes your leave-by time.
These are conservative planning estimates, not guarantees. Conditions
vary by airport, day, and TSA wait times — when in doubt, add buffer.
🗂️ The data
- Airports
- —
- With scheduled service
- —
- Source
- OurAirports (public domain)
- Last refreshed
- —
The airport list comes from OurAirports, a public-domain dataset. We
keep 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 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 and reflects the snapshot date
above. Spot something off? It’s an estimate — adjust any field to match your reality.