What should I pack in a carry-on only?

A carry-on only trip comes down to one principle: everything you bring should work with everything else. The standard formula for a 3–5 day trip is the “X-Y-Z” system: 1 jacket or sweater, 2 bottoms (pants or skirts), and 3 tops, all in a color palette that mixes and matches. That gives you 6–9 different outfits from 6 items of clothing. Add versatile shoes (a pair of walking shoes plus sandals or dress shoes that serve double duty) and you’re set.

The TSA 3-1-1 rule limits liquids to 3.4 ounces (100 ml) per container, all fitting in a single quart-sized clear bag. Solid toiletries like shampoo bars, toothpaste tablets, and stick deodorant don’t count toward the limit and save space. Packing cubes compress clothes and keep your bag organized enough that you can find things without unpacking everything.

The big weight decision is the bag itself. A 20–22 inch roller bag is the standard carry-on size for most airlines, but a soft-sided backpack or duffel is lighter and easier to stow in a crowded overhead bin. Check your airline’s size limits before you leave — budget carriers often use tighter dimensions than full-service airlines.