How we know: Sources are listed at the end. Rules are quoted from the TSA, a major US airline and the CDC; airline allowances differ, so check yours before you fly.
Carry-on only is not a personality; it is a set of habits that save time at both ends of every flight, remove the risk of a lost bag, and turn low-cost fares that exclude checked luggage into genuinely cheap tickets. Two weeks abroad in one bag is routine once you accept two ideas: you will do laundry, and nobody will notice you wore that shirt twice.
The rules that shape the bag
- Size. Delta's limit, typical of US carriers, is 22 x 14 x 9 inches (56 x 35 x 23 cm) including wheels and handles, plus one personal item that fits under the seat (Delta). European and Asian airlines, and US low-cost carriers, are often stricter on size or weight, and some basic fares include only the personal item. Check the specific airline for each leg.
- Liquids. Containers of 3.4 ounces (100 ml) or less, all fitting in one quart-size bag; medications and infant nourishment are exempt from the limit (TSA). Duty-free liquids bought abroad can transit US connections if sealed in the tamper-evident bag with the receipt.
- Health kit. The CDC recommends prescriptions in their original containers with copies of the prescriptions, a basic first-aid kit, insect repellent with DEET or picaridin, and broad-spectrum sunscreen (CDC Pack Smart). Check the destination's rules on medications, which can be stricter than at home.
The bag itself
A soft-sided 40-litre backpack or a 21-inch spinner both work; the backpack survives cobblestones and stairs, the spinner survives airports. Either way, buy to the smallest allowance you will face on the trip, not the largest. A packable day bag as your personal item does double duty at the destination.
A two-week list that fits
Clothing (choose colours that all match):
- 5 tops, 2 bottoms, 1 layer (fleece or light sweater), 1 packable rain shell
- 5–7 underwear, 4–5 pairs of socks, sleepwear, swimwear if relevant
- 1 dressier outfit or a shirt that can be dressed up
- Shoes: the pair on your feet plus one other
Toiletries: solid versions of shampoo, conditioner and soap avoid the liquids bag entirely; decant the rest into small bottles.
Electronics: phone, charger, one universal adapter, a small power bank, headphones. Leave the laptop unless you will work.
Documents: passport, copies stored separately, cards, a little cash, insurance details offline.
Wear the bulk. Boots, the heaviest layer and the jacket go on you, not in the bag.
Laundry is the whole trick
Plan a wash every five to seven days: a hotel or hostel machine, a laundrette, or a sink and a travel clothesline. Quick-dry fabrics (merino, synthetics) dry overnight; cotton does not. This one habit is what makes two weeks in a 40-litre bag comfortable rather than austere.
What to leave behind
- "Just in case" items. If you need it, you can buy it there.
- More than two pairs of shoes.
- Full-size toiletries and towels.
- Guidebooks; download the content.
- Anything you have not worn in the last month at home.
Why it saves money
Low-cost transatlantic and transpacific carriers sell seat-only fares; the checked bag is where the price climbs. Travelling with a compliant carry-on lets you take the base fare at face value on airlines such as Norse, French Bee and ZIPAIR (see our budget airlines to Europe guide). It also makes separate-ticket connections and positioning flights far less risky, because there is no bag to re-check. Watch the fare on your route, for example JFK to London, Newark to Paris or LAX to Tokyo, and set a price alert.
FAQ
What size carry-on is allowed on international flights? US carriers typically allow 22 x 14 x 9 inches; many foreign and low-cost carriers are stricter and some impose weight limits. Check each airline on your itinerary.
Can I bring medication in my carry-on? Yes; the TSA exempts medications from the liquids limit. Keep prescriptions in original containers with copies.
How do I pack two weeks in a carry-on? Limit yourself to about five tops and two bottoms in matching colours, wear the bulky items, use solid toiletries, and do laundry once a week.