Any standard carry-on bag can easily hold enough clothing for four days, provided your outfits can share just one or two pairs of shoes. This will only become trickier during colder visits when you'll need to bulk up.

For a 4-day trip in 2026, a standard carry-on (typically 40–45 liters) is more than sufficient, provided you utilize efficient packing techniques. The key is the "5-4-3-2-1" rule or the use of compression packing cubes, which allow you to maximize the internal volume of the bag. A 4-day itinerary usually requires four changes of underwear and socks, two to three shirts, one extra pair of trousers or a skirt, and one versatile pair of shoes worn on the plane. Since most modern travelers prioritize "capsule wardrobes"—mixing and matching neutral colors—you can easily fit these items along with a small toiletry bag and a laptop. Carrying only a cabin bag saves significant time by bypassing baggage carousels and avoids the increasingly high checked-luggage fees charged by airlines like Ryanair or Spirit. With the rise of "personal item only" travel in 2026, a full-sized carry-on for just four days is actually considered quite generous and allows for extra space for souvenirs.