How these wait times are worked out
Two different kinds of number appear on this site, and we label which is which on every page.
Two kinds of number
Some numbers here are measured: an agency counted them and we pass the count through untouched. Others are modeled: we start from a measured fact and apply stated assumptions to reach a figure the source itself never published. Every page says which kind it is showing, and the sections below explain how each one is made.
Border crossings: measured
Every border number on this site is CBP's own. U.S. Customs and Border Protection publishes a live feed of delays at all 75 land crossings it staffs, broken out by passenger vehicles, pedestrians and commercial trucks, and again by general, Ready and trusted traveler lanes. We read that feed directly in your browser, so what you see is what CBP is publishing at that moment, not a copy we cached this morning.
When a lane shows no reading, CBP is not reporting on it. That usually means the lane is closed. We show the gap rather than filling it with a plausible number.
Airport security: the shape is measured, the minutes are modeled
There is no national feed of TSA checkpoint waits. Anyone who shows you a live security wait for every US airport is showing you an estimate, whether they say so or not. We would rather say so, and then explain the estimate.
What is measured
The Bureau of Transportation Statistics publishes every scheduled departure by every reporting airline: the airport, the local departure time, the date. We use three months of it, more than 1.8 million departures, to build the hour-by-hour departure load at each of the 355 airports on this site. That is the real driver of a checkpoint queue, and it is a fact, not a guess. It is what the shaded grid on every airport page shows.
One limit of that source, stated plainly: "reporting airline" means the US carriers required to file with BTS. Foreign airlines do not report, so at international gateways such as JFK, Miami, Dulles and Honolulu the departure load we measure is the domestic share, and the modeled wait there leans low. The same gap applies to the "airlines flying from" list on each airport page, which counts only reporting carriers. Where such an airport publishes an official live feed, the live number replaces the model.
What is modeled
Turning that load into minutes takes three assumptions, and here they are in full:
- Passengers reach the checkpoint ahead of their own departure, spread across the preceding hours rather than all at once. We weight a flight's contribution to a given hour's queue at 10 percent for the hour it departs, 45 percent one hour earlier, 32 percent two hours earlier and 13 percent three hours earlier.
- An airport's checkpoint capacity scales with the traffic it was built for, so what matters is how hard an airport is pushing against its own peak, not its size in absolute terms. A large hub at full stretch has a wider spread between its quietest and busiest hour than a regional field does.
- Queues grow faster than load once a checkpoint approaches capacity, so the curve is bent rather than straight.
Because the minutes are modeled, we publish a band rather than a single number. A page that tells you the wait is exactly 23 minutes is telling you something it cannot know.
The three lanes
Standard is the number above. PreCheck runs roughly a third of it, floored at a few minutes because no lane is instant and capped so it never claims an implausibly short wait at a jammed checkpoint. CLEAR is shorter still. It is not a lighter screening but a queue position, so we model it just below PreCheck and never at zero, because you still walk through the same scanner behind whoever CLEAR placed ahead of you.
Per-terminal waits
Where an airport splits across terminals that each run their own checkpoint, we show a wait for each. These are modeled, not measured, the same way the airport figure is. We attribute each airline's departures to its terminal, from a hand-curated airline-to-terminal table, and scale the wait by how hard that terminal's checkpoint is pushing against the busiest one at the airport. The busiest terminal reads the airport number and the quieter ones read less. It is a model and a band, not a measurement, and it appears only for the airports where we have the terminal assignments.
The leave-by calculator
The two-hour rule treats every airport, every hour and every traveler the same. They are not. A Tuesday-evening flight from a quiet regional field and a Monday 7 a.m. flight from a big hub are different problems, and the gap between them is often wider than the two hours the rule sets aside. The calculator reads the departure schedule at your actual airport, works out how loaded the checkpoint is at the hour you would reach it, and adds the steps that come before and after security. Each step carries its own minutes, so you can disagree with any one of them instead of trusting a single total.
Here is what each step covers.
| Drive | Your own estimate, or a real drive time when you give us an address to time it from. Traffic to a big airport at rush hour is usually the least predictable part of the whole chain. |
|---|---|
| Park and shuttle | Economy lot to terminal door, including the wait for the bus, scaled to the size of the airport. Turn it off if someone is dropping you at the curb. |
| Bag drop | The counter or kiosk queue. Airlines stop accepting checked bags 45 minutes before a domestic departure and 60 before an international one, and the calculator moves your leave-by time earlier if you would miss that cutoff. |
| Security | The modeled queue at the hour you arrive, not the airport's daily average. PreCheck and CLEAR run roughly a third of the standard line. |
| Walk to gate | Security exit to the gate, including the train at airports that have one. |
| At the gate | Once we know your airline, we use its own published boarding deadline: the point after which you can be denied boarding. Most carriers close boarding 15 minutes before a domestic departure and 30 before an international one, but a few differ. Southwest cuts off 10 minutes out, while Alaska, Hawaiian and Allegiant want you at the gate a full 30 minutes ahead. Without a resolved flight we assume 15 and 30. Being at the airport is not the deadline; being at the gate is. |
Terminal walk times: real gate positions, modeled minutes
On the terminal-map pages we show how long it takes to walk from the security
checkpoint to each gate. The geometry is real: every gate is an actual
coordinate from OpenStreetMap, whose aeroway=gate nodes cover the
major US airports gate for gate. The one thing no dataset publishes is where the
checkpoint itself is, so we place that by hand, one point per terminal, and mark
each one unverified until it is checked against the airport's own map.
The minutes are modeled, the same way the security waits are. We take the straight-line distance from the checkpoint that serves a gate, multiply by a corridor factor of 1.3 because nobody walks through walls, and divide by a measured free-flow walking speed of 264 feet per minute, with a standard deviation of 52 feet per minute, from Airport Cooperative Research Program (ACRP) Report 67. Because both the path and the walker vary, the answer is a band rather than a single number. It does not include moving walkways, escalators or a train between concourses: it is the walk, on foot. We publish a terminal page only where the gate coverage is real and a checkpoint has been placed, because without the walk minutes there is nothing on the page a plain map does not already have.
Ferries: a published timetable and a modeled boarding buffer
The ferry pages read the Washington State Ferries schedule and, where the feed carries them, vessel positions and per-sailing car-deck space. The schedule is a published timetable, not a model. Vessel positions carry the operator's own observation time and are baked at each rebuild, not tracked moment by moment, and the page says so; the crossing duration is shown only where WSF actually publishes it, and left blank where it does not.
The one modeled number is the boarding buffer: to turn a sailing time into a leave-by we assume you should reach the tollbooth 20 minutes before departure, which is WSF's own advice for a drive-up vehicle. So leave home = sailing time − your drive to the dock − 20 minutes. Change the drive to your own and the answer moves with it; the buffer is the single assumption, stated on the page and here.
What we will not do
We do not publish checkpoint opening hours we cannot source, we do not invent live numbers for airports that publish none, and we do not quietly turn a model into a measurement. Where an airport runs its own official live wait feed, that number wins and the model steps aside; those are being added one airport at a time.
Sources
- U.S. Customs and Border Protection, border wait times feed.
- U.S. Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, May 2026, July 2025 and December 2025.
- OurAirports and OpenFlights for airport names, locations and time zones.