The Carry-On-Only Packing Guide: Pack a Week in One Bag

A practical system for traveling carry-on only: airline size limits, the TSA 3-1-1 liquids rule, power bank rules, a complete checklist and common mistakes to avoid.

10/15/20266 min read

Traveling with only a carry-on is one of the simplest ways to save money and time. You skip checked-bag fees, you skip the baggage carousel, and you never have to wonder whether your suitcase made the connection. It does take a plan, though. This guide walks through the rules you have to work within, a packing system that holds up for a week or more, and the mistakes that most often send carry-on travelers back to the check-in counter.

Affiliate disclosure: This guide contains one optional link to our gear page, which includes affiliate links. If you buy through them, It's Yo Worl may earn a commission at no extra cost to you. Nothing in this guide requires buying anything.

Step 1: Know Your Limits Before You Pack

Bag size

Most major U.S. airlines publish a carry-on limit of 22 x 14 x 9 inches, including wheels and handles. Alaska Airlines and Delta both list that size, plus one smaller personal item (a backpack, purse or laptop bag) that must fit under the seat in front of you. Delta adds a 45-linear-inch cap.

Two things trip people up:

  • Wheels and handles count. A bag sold as "22-inch" may measure 23 or more once you include the wheels. Measure your own bag with a tape measure, fully packed, because soft bags bulge.

  • Your fare type matters. Some basic economy fares do not include a full-size carry-on at all. United, for example, limits most Basic Economy tickets to one personal item (published maximum 9 x 10 x 17 inches), with exceptions for certain long-haul routes and some elite and cardholder customers. Check the exact fare rules on your ticket before you assume an overhead-bin bag is included.

Liquids: the TSA 3-1-1 rule

The TSA still allows one quart-sized bag of liquids, aerosols, gels, creams and pastes per traveler, with each container 3.4 ounces (100 milliliters) or less. Anything larger goes in checked luggage. Medications and infant or child nourishment are exempt, though they may get extra screening.

The rule is about the container size, not how much is inside. A half-empty 6-ounce bottle of sunscreen will still be pulled. Decant into small refillable bottles or buy travel sizes.

Batteries and power banks

According to the FAA and TSA, spare lithium batteries and power banks must go in your carry-on, never in checked bags. The FAA allows spares up to 100 watt-hours without airline approval; 101 to 160 Wh requires airline approval and is limited to two spares; over 160 Wh is not allowed on passenger aircraft.

Airlines are allowed to be stricter, and many now are. Delta, for example, limits each traveler to two power banks of up to 100 Wh each, says they may not go in the overhead bin, and bars recharging them on board. Southwest, as of April 20, 2026, allows one power bank per customer (100 Wh maximum) and says it must be visible, not stored in a bag, while in use. Keep your power bank in your personal item under the seat so you never have to dig for it, and check your airline's current battery page before you fly.

ID at the checkpoint

Since May 2025, TSA checkpoints require a REAL ID-compliant license or another acceptable ID such as a passport. Starting February 1, 2026, travelers without acceptable ID can pay a $45 TSA ConfirmID fee for TSA to try to verify their identity. That doesn't guarantee you get through, so bring a compliant ID. Under a policy announced in July 2025, most travelers can now keep their shoes on at standard TSA screening, though officers can still ask for extra screening.

Step 2: Choose the Right Two Bags

Carry-on-only travel is really a two-bag system:

  1. The carry-on holds clothing and anything you won't need in flight.

  2. The personal item holds everything you need on board or at security: ID, wallet, phone, chargers, power bank, medications, liquids bag, headphones, a light layer and any valuables.

Soft-sided bags tend to squeeze into sizers and tight bins more easily. Hard-shell bags protect fragile items better but give you less wiggle room. Whatever you use, pack it fully at home and try lifting it overhead. If it's a struggle in your living room, it'll be worse in a crowded aisle.

Step 3: Build a Capsule Wardrobe

The real secret to packing light is fewer, more versatile clothes, not better folding. A simple formula for a 5-to-7-day trip:

  • Tops: 4 to 5 that all go with every bottom

  • Bottoms: 2 to 3 (for example, one pair of jeans or travel pants plus one lighter option)

  • One mid-layer: a sweater, fleece or overshirt

  • One outer layer: a packable rain jacket or insulated jacket, depending on destination

  • Shoes: 2 pairs maximum. Wear the bulkiest pair on the plane.

  • Underwear and socks: 4 to 7 sets, or fewer if you plan to wash in the sink or use a laundromat

  • Sleepwear and one "nicer" outfit if your plans call for it

Pick one neutral color family (black, navy, gray, tan) and add color with one or two pieces. When everything matches everything, five tops and three bottoms make fifteen outfits.

Plan laundry instead of packing for every day. For trips longer than a week, packing for 5 to 7 days and doing laundry once is usually lighter and cheaper than adding a checked bag. Many hotels and rentals have machines, and a small packet of travel detergent covers a sink wash.

Step 4: Pack in the Right Order

  1. Shoes first, along the bottom or the wheel side. Stuff socks or chargers inside them.

  2. Roll or fold soft clothing into packing cubes. Rolling works well for t-shirts and knits. Folding is often better for structured items. Compression cubes squeeze out air, but the bag has to stay within its outside dimensions and any weight limit.

  3. Fill the gaps. Belts go around the edges, and underwear tucks into corners.

  4. Flat items last. A jacket or sweater laid on top keeps everything compressed.

  5. Toiletries and electronics go in the personal item, so you can pull your liquids bag and power bank out quickly.

Step 5: The Carry-On Checklist

In your personal item (keep accessible): - REAL ID-compliant ID or passport, plus boarding pass (digital and a screenshot) - Wallet, a backup payment card stored separately - Phone, charging cable, wall plug, power bank (check the watt-hours) - Prescription medications in original labeled containers, plus a copy of prescriptions - Quart-sized bag with 3.4 oz / 100 ml containers - Headphones, glasses or contacts, and any medical devices - An empty refillable water bottle (fill it after security) - A light layer for cold cabins - Snacks (solid foods are generally fine; spreads and dips count as liquids) - Pen, for arrival forms on international trips

In your carry-on: - Capsule wardrobe (above) in packing cubes - Second pair of shoes - Sleepwear - Swimsuit or workout clothes if needed - Small laundry kit - Universal travel adapter for international trips - Foldable tote or daypack for day trips and souvenirs

Before you leave home: - Check your fare to confirm a full carry-on is included - Check your airline's battery and power bank rules - Weigh your bag if your airline (common outside the U.S.) sets a carry-on weight limit - Photograph your passport and ID and store the photos securely - Check the weather and swap one item if needed. Don't add one.

Common Carry-On Mistakes (and How to Avoid Them)

  • Forgetting the wheels. Measure the whole bag, not the advertised size.

  • Full-size toiletries. Big containers are the most common reason bags get pulled at security. Decant before you go.

  • Power bank in the overhead bin. Many airlines now prohibit it. Keep it under the seat.

  • Packing "just in case" outfits. If you can't name the day you'll wear it, leave it home.

  • Boarding late. On full flights, bin space runs out and late boarders may be asked to gate-check. Boarding with your group, and having a bag small enough to slide under a seat in a pinch, protects you.

  • Ignoring the return trip. Leave roughly 10 percent of your bag empty for anything you pick up along the way, or pack a foldable tote that can become your personal item on the way home.

The Bottom Line

Carry-on-only travel comes down to four habits: know your airline's size and fare rules, respect the 3-1-1 liquids limit, keep batteries in the cabin, and pack a capsule wardrobe you can re-wear. Once you've done it once, it's hard to go back to waiting at the carousel.

Looking for bags or packing cubes? We keep a short list on our Luggage & Travel Gear page (contains affiliate links).

Rules change. Check the official TSA, FAA and airline pages linked below before every trip.

Sources (verified October 14, 2026)

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