A useful carry-on packing checklist starts with your booked airline's bag allowance and the security rules at every airport on your route. Then pack documents, necessary personal items, clothing and electronics around those limits. A bag that fits one airline or passes one airport is not automatically suitable for the return journey.
This checklist covers practical preparation for journeys involving the United States, United Kingdom and Canada. Security information was checked on 8 September 2026. Recheck official guidance before departure, particularly for medical supplies, batteries and connecting flights.
Confirm the limits before choosing a bag
Check the allowance attached to your fare, including the difference between a personal item and an overhead cabin bag. Measure the packed bag as the airline instructs, including handles or wheels where required. There is no single carry-on dimension or weight allowance that applies to every carrier.
If one allowance uses centimetres and another uses inches, use the cm-to-inches converter. For weight, use the kg-to-lb converter. Conversion changes the units, not the allowance, and rounding down does not make an oversized bag compliant.
Pack the essentials where you can reach them
- Bring the identification and travel documents required for your exact journey, plus accessible booking details.
- Keep necessary medication and supporting documents available for screening. Check the relevant exemption procedure rather than applying the ordinary toiletries rule to medical supplies.
- Pack a phone, compatible charging cable and any needed adapter.
- Include a practical change of clothing and personal essentials for a delay.
- Keep valuables and items you need during the flight in a smaller bag that can remain with you if the larger bag is taken at the gate.
For clothing, plan around the activities, weather and laundry access on the trip. A three-day visit with one formal event needs a different selection from three days of outdoor activities. Lay out actual outfits before adding spare items, then leave enough room to repack without forcing the zip.
Check liquid rules by departure airport
| Screening location | Ordinary carry-on liquids | What to verify |
|---|---|---|
| United States | TSA's 3-1-1 rule uses containers of 3.4 ounces or less in one quart-sized bag per passenger | Medical and other exemptions; current TSA instructions |
| Canada | CATSA specifies containers of 100 ml or 100 g or less in one clear, resealable bag of no more than 1 litre | Exempt items and separate screening requirements |
| United Kingdom | Rules vary by airport; most use a 100 ml container limit, while some allow containers up to 2 litres | Departure, transfer and return airports; whether a separate bag is required |
The limits above come from TSA's travel checklist, CATSA's liquids guidance and the UK government's airport liquids guidance. Read the linked exemptions for your circumstances. A partly filled large container may still exceed a container-size restriction.
A practical example is a UK departure airport that accepts a larger container followed by a return airport with a 100 ml limit. Packing for only the outbound rule can leave you unable to take the same toiletries home in cabin baggage. An empty refillable bottle avoids carrying ordinary drinking water through screening, subject to the airport's instructions.
Keep spare batteries out of a gate-checked bag
For US-regulated air travel, the FAA's lithium-battery guidance requires spare lithium batteries and power banks to remain in carry-on baggage. If the bag is checked at the gate, remove those items and retain them in the cabin. Protect terminals against short circuits.
Check the battery's watt-hour marking and your airline's restrictions before packing. Airlines can impose stricter quantity or capacity rules. Damaged or recalled batteries need specific attention under official guidance; do not assume moving one to checked baggage makes it acceptable.
Run the final check at home
Weigh and measure the packed bag, then practise removing the items you may need at screening. Confirm documents, medication arrangements, liquid containers and battery placement. Keep your onward journey and return route in the same checklist.
For a dated reminder before departure, use the date calculator. It counts calendar days; it does not determine passport validity, visa eligibility or an airline's check-in deadline. Those requirements must come from the relevant official service and your booking.