"How many days do I need in Chicago?" is the question everybody asks and nobody answers with anything you could check. The usual reply is a shrug in prose: three is rushed, four is comfortable, five is relaxed.
We had a way to test it. Our planner is deterministic, so the same city at three, four and five days produces the same plan every time, and the difference between those plans is a fact rather than an opinion. We built all three lengths for ten US cities, thirty finished itineraries, and then counted.
The answer was not the one we expected.
The fourth day does not give you more city
Here is what the extra days actually add, counted in stops:
| City | 3 days | 4 days | 5 days |
|---|---|---|---|
| Boston | 14 | 15 | 20 |
| Chicago | 13 | 14 | 19 |
| Las Vegas | 15 | 16 | 21 |
| Los Angeles | 16 | 16 | 21 |
| Miami | 14 | 15 | 19 |
| New Orleans | 15 | 16 | 20 |
| New York City | 11 | 12 | 16 |
| San Francisco | 15 | 18 | 22 |
| Seattle | 16 | 17 | 22 |
| Washington, D.C. | 13 | 15 | 20 |
Going from three days to four adds one stop in most cities. Los Angeles adds none at all. Going from four to five adds four or five.
That looks broken until you see what the fourth day is.
The fourth day is one thing, all day
In all ten cities the fourth day became a single full-day anchor: one stop, the entire day. Eight of the ten leave the city to do it.
| City | What the fourth day is | Out of town? |
|---|---|---|
| Boston | Cape Cod National Seashore | Yes |
| Chicago | Indiana Dunes National Park | Yes, and out of state |
| Las Vegas | Hoover Dam | Yes |
| Miami | Everglades National Park | Yes |
| New Orleans | Oak Alley Plantation | Yes |
| New York City | Storm King Art Center | Yes, upstate |
| San Francisco | Napa Valley | Yes |
| Seattle | Mount Rainier National Park | Yes |
| Los Angeles | Universal Studios Hollywood | No, it is in the metro |
| Washington, D.C. | The Smithsonian | No, it is on the Mall |
That is why the stop count barely moves. Boston at four days is 5 + 4 + 5 + 1, and the 1 is Cape Cod.
The two exceptions are the two cities big enough to contain a full day inside themselves. Washington does not need to leave to spend a day in one institution, and Los Angeles does not need to leave to spend one in a theme park.
Nothing about this was hand-tuned per city. The planner reserves a full-day anchor once a trip is long enough to spare one, and it picks the least iconic interior day to spend rather than a day carrying a must-see. Ten out of ten cities landed on an excursion at exactly four days.
So the real question is not "how long"
It is "do I want the day trip?"
- Three days is the city, done properly. In most of these cities that is 13 to 16 stops and it does not feel thin.
- Four days is the city plus one big thing. You are buying Cape Cod or Mount Rainier, not more Boston or more Seattle.
- Five days is the city, the excursion, and then genuinely more city: another four or five stops back in town.
If someone tells you four days in Seattle so you can really see the city, they have it backwards. Four days in Seattle is three days of Seattle and a day at Mount Rainier. If you want more Seattle, book five.
Where this does not hold
Two honest caveats.
Los Angeles is different. Three days already spends sixteen stops covering a city that is ninety minutes end to end, and the fourth day at Universal Studios adds no stops at all. LA is the one city here where four days is not obviously better than three unless you specifically want the theme park.
San Francisco is the exception the other way. It gains three stops on the fourth day rather than one, because the city is compact enough that a Napa day still leaves an afternoon.
Read them yourself
Every itinerary behind this post is free to read with no account, at three, four and five days:
- Boston · Chicago · New Orleans
- Las Vegas · Los Angeles · Miami
- New York City · San Francisco · Seattle · Washington, D.C.
Or see the whole plan library, which has all three lengths for each. If your city is not in that list, it is probably still vetted: 111 cities, 63 national parks and all 50 states, and you can build any of them for your own dates.