Last Updated on July 31, 2026 by Daniel Globe
Southwest Airlines gives each ticketed passenger a generous carry-on allowance, but the bag still has to meet the airline’s size and storage rules. Measuring the full outside of your luggage before leaving home can prevent repacking at the airport and help you decide whether a smaller bag is needed.
Quick Answer
Southwest allows each ticketed passenger one free carry-on bag up to 24 x 16 x 10 inches, including wheels and handles, plus one personal item that fits under the seat. Southwest currently publishes no numeric carry-on weight limit or fixed personal-item measurements. Oversized bags must be checked, and checked-bag fees may apply.
Key Takeaways
- The Southwest carry-on size limit is 24 x 16 x 10 inches, including wheels, handles, and attachments.
- You may also bring one personal item, but it must fit under the seat in front of you.
- Southwest does not list a numeric carry-on weight limit in its current public policy.
- A bag that is too large or an extra bag must be checked, and standard checked-bag fees may apply.
- Effective April 20, 2026, each passenger may bring only one power bank, rated at 100 Wh or less, and it must stay under the seat rather than in the overhead bin.
At a Glance
| Time Required | About 5–10 minutes to measure and repack |
| Difficulty | Easy |
| Tools Needed | Tape measure or ruler; luggage scale optional |
| Cost | Free to measure; checked-bag fees may apply if the bag is not compliant |
Southwest Airlines Carry-On Size and Allowance
Under Southwest’s current carry-on and personal-item policy, every ticketed passenger may bring one carry-on bag and one personal item onboard at no additional charge.
The maximum carry-on size is 24 inches long by 16 inches wide by 10 inches high, and the measurement includes wheels, handles, pockets, and other attachments.
| Item | Current rule | Storage location |
| Carry-on bag | Maximum 24 x 16 x 10 inches; no published numeric weight limit | Overhead bin |
| Personal item | No fixed public measurement; it must fit under the seat | Under the seat in front of you |
| Lap child | No separate checked or carry-on baggage allowance | Items must fit within the accompanying passenger’s allowance |
What Counts as a Personal Item?
Common personal items include a purse, crossbody bag, briefcase, laptop case, small backpack, blanket, pillow, or small camera. Southwest says the item must fit under the seat in front of you. Its current public policy does not give a fixed personal-item measurement, so the older 18.5 x 8.5 x 13.5-inch figure should not be treated as a current airline limit.
A neck pillow does not count toward the carry-on limit. A pet carrier does count as either your carry-on bag or your personal item. Keep medicines, travel documents, keys, electronics, and valuables in the personal item so they remain easy to reach.
Note: If any part of your itinerary is operated by a partner airline, that carrier’s baggage measurements and item limits may apply to its segment.
Is There a Carry-On Weight Limit?
Southwest’s published carry-on policy gives a size limit but does not list a numeric weight limit. The 50-pound figure applies to a standard checked bag, not a carry-on. Pack the bag so it can be handled safely and stowed without forcing it into the overhead bin.
Tips for Packing a Southwest Carry-On Bag
Start with a short packing list based on the weather, trip length, and activities at your destination. Separate the list into clothing, toiletries, electronics, documents, medicine, and must-have items. This makes it easier to remove duplicates before the bag becomes overstuffed.
- Use packing cubes: Group shirts, underwear, accessories, and sleepwear so you can find items without unpacking everything.
- Roll soft clothing: Rolling can reduce empty gaps and help limit wrinkles.
- Wear bulky pieces: A jacket, sweater, or boots can be worn through the airport instead of taking up most of the suitcase.
- Use small containers: Carry-on liquids, aerosols, gels, creams, and pastes generally must be in containers of 3.4 ounces or 100 milliliters or less and fit in one quart-size bag under the TSA 3-1-1 rule.
- Keep essentials under the seat: Put medicine, chargers, identification, a change of clothes, and valuables in your personal item.
Pro Tip: Pack the bag first and measure it while full. Soft-sided luggage can expand beyond the limit even when its empty dimensions appear compliant.
For a comfortable flight, small accessories can also help. For example, merino wool travel socks take little space and may be useful on long travel days.
Choosing the Right Carry-On Bag for Southwest Airlines
Choose a bag whose listed external dimensions are at or below 24 x 16 x 10 inches. Do not rely only on labels such as “cabin size” or “airline approved,” because brands may measure the shell without fully accounting for wheels, handles, feet, or an expanded zipper panel.
A lightweight bag leaves more room for your belongings and is easier to move through the airport. Look for reinforced seams, smooth zippers, sturdy handles, and wheels that do not add too much height. Multiple compartments can keep documents and electronics accessible, while compression straps help stop the contents from shifting.
Hard-shell bags protect fragile contents but have little flexibility when overpacked. Soft-sided bags can fit awkward spaces more easily, but exterior pockets and expansion panels may push them beyond the allowed size. A compact backpack can work well for short trips as long as it remains within the carry-on dimensions.
How to Measure Your Carry-On Bag
- Pack the bag as you plan to travel. Close every zipper, including expansion panels, and do not press the bag flat.
- Measure the longest side. Include wheels, handles, feet, and anything else that extends beyond the main shell. This measurement must be no more than 24 inches.
- Measure the width. Check the widest point, including side handles and stuffed outer pockets. It must be no more than 16 inches.
- Measure the depth. Measure from front to back at the thickest point. It must be no more than 10 inches.
Measure twice and check the bag from more than one point. A soft bag may bulge near the center, while wheels may make one end taller than the other.
Warning: Do not measure only the fabric body. Wheels, fixed handles, protective feet, external pockets, and attachments all count toward Southwest’s 24 x 16 x 10-inch limit.
What to Do If Your Bag Is Too Large
If the packed bag exceeds any measurement, remove nonessential items or move them into a compliant personal item. You can also transfer the contents to a smaller suitcase, duffel, or backpack. Southwest advises passengers with an oversized bag or more than one carry-on and one personal item to check the extra item at the ticket counter before going to the gate.
Checked-bag fees depend on the fare, status, route, and booking date. For U.S. mainland travel booked, ticketed, or changed on or after April 9, 2026, Southwest currently charges Basic, Choice, and Choice Preferred passengers $45 for the first standard checked bag and $55 for the second. Choice Extra includes two standard checked bags, while qualifying Rapid Rewards status or credit-card benefits may provide free bags. Review Southwest’s current optional travel charges before departure because fees can change.
Shipping luggage ahead may make sense for unusually large or specialized items, but compare the full courier cost, delivery time, insurance, and destination access before choosing that option.
Personal Items, Children, Pets, and Special Cases
Children and Lap Infants
A lap child does not receive a separate baggage allowance. However, when a seat has been purchased for a child, an FAA-approved child restraint system used during the flight may be brought onboard without counting toward the carry-on limit. Southwest also allows an accompanying passenger to check one stroller and one car seat or child-restraint system per child at no charge under its child-item policy.
Pet Carriers
An in-cabin pet carrier counts as either the carry-on bag or the personal item. A passenger traveling with a pet may therefore bring the carrier plus only one other allowed item.
Food, Purchases, and Extra Bags
Do not assume that airport food, shopping bags, or duty-free purchases create an extra baggage allowance. Keep the total number of items within Southwest’s one-carry-on-plus-one-personal-item rule, or consolidate small purchases before boarding.
Carry-On Safety and TSA Rules
Southwest’s size rule is only one part of carry-on compliance. TSA and FAA restrictions also control what can travel in the cabin. Use the TSA’s official What Can I Bring? search before packing sharp objects, sporting goods, tools, food, or other unusual items.
- Liquids: Most liquids, aerosols, gels, creams, and pastes must follow the 3-1-1 rule: containers of 3.4 ounces or 100 milliliters or less inside one quart-size bag.
- Spare lithium batteries: Spare lithium batteries and power banks belong in the cabin, not checked baggage. Protect terminals from short circuit.
- Prohibited items: Explosives, many flammable materials, and other hazardous items are not allowed. Firearms are not permitted in carry-on bags and are subject to separate declared checked-baggage rules.
- Medicines and valuables: Keep medicines, keys, identification, money, and fragile electronics with you rather than in a bag that may need to be checked.
Warning: Effective April 20, 2026, Southwest limits each passenger to one power bank of no more than 100 Wh. It must stay in the cabin, cannot be placed in the overhead bin, should be stored in a personal item under the seat, may not be charged from in-seat power, and must remain visible while in use. Check Southwest’s current battery policy before flying.
The FAA battery guide also states that ordinary lithium-ion batteries up to 100 Wh are generally allowed, batteries from 101 to 160 Wh require airline approval, and batteries above 160 Wh are forbidden on passenger aircraft. Southwest’s newer one-power-bank, 100-Wh rule is more restrictive and controls on Southwest flights.
Frequently Asked Questions
What is the Southwest Airlines carry-on size limit?
The maximum carry-on dimensions are 24 x 16 x 10 inches. Wheels, handles, feet, pockets, and other attachments must be included in the measurement.
Does Southwest have a carry-on weight limit?
Southwest’s current public carry-on policy does not list a numeric weight limit. The commonly cited 50-pound limit is for standard checked baggage, not carry-on luggage.
Can I bring a personal item in addition to my carry-on?
Yes. Each ticketed passenger may bring one carry-on bag and one personal item at no extra charge. The personal item must fit under the seat in front of you.
What are Southwest’s personal-item dimensions?
Southwest’s current public policy does not publish a fixed personal-item measurement. It says the item must fit under the seat in front of you.
What happens if my carry-on is too large?
The bag must travel as checked baggage. Southwest recommends checking an oversized or extra bag at the ticket counter before going to the gate. Standard checked-bag fees may apply based on your fare, route, status, and benefits.
Do I pay for a carry-on bag on Southwest?
No. Southwest allows one compliant carry-on bag and one personal item free for each ticketed passenger. Fees may apply when an oversized or extra item has to be checked.
Can I pack a power bank in my Southwest carry-on?
Yes, but Southwest permits only one power bank per passenger, it must be 100 Wh or less, and it must be kept in the cabin under the seat rather than in the overhead bin. It cannot be charged onboard and must be visible while in use.
What items are not allowed in a carry-on bag?
Explosives, many flammable materials, firearms, and various sharp or hazardous items are prohibited from carry-on baggage. Because rules vary by item, check the TSA’s official What Can I Bring? database before packing.
Measuring a fully packed bag, keeping the personal item small enough for under-seat storage, and checking current battery and security rules can prevent most carry-on problems. Recheck Southwest’s policy shortly before departure, especially when a partner airline is included in the itinerary.
Sources
- Southwest Airlines Carry-On and Personal Item Policy — carry-on dimensions, item count, storage, pet carriers, and partner-airline notice
- Southwest Airlines Optional Travel Charges — current checked-bag fees and fare/status exceptions
- Southwest Airlines Battery and Power-Bank Policy — Southwest’s April 2026 power-bank restrictions
- Transportation Security Administration Liquids Rule — the 3-1-1 carry-on liquids requirements
- Federal Aviation Administration Airline Passengers and Batteries — lithium-battery watt-hour limits and carry-on safety requirements
