Checked Baggage

Checked baggage has a reputation as the place where anything goes, as long as it zips shut. That reputation is wrong in one big way. Spare lithium batteries and power banks are banned from the hold, and have to travel in the cabin with you instead.

Get that one backward and the consequences range from annoying to serious. A gate agent may pull your bag open to fish out a forgotten power bank. Or nobody catches it, and a battery fault becomes a fire risk in a cargo hold nobody is watching.

This page covers the numbers, the fees, the security rules, and the timing. The goal is to make checked baggage predictable instead of a gamble.

The one thing that cannot go in the hold

Spare lithium ion batteries and power banks must fly in carry-on baggage, never in a checked bag. The FAA is explicit about this. If a bag gets checked at the gate after you already boarded with it, pull the batteries and any power bank out first and keep them with you.

This surprises people because it is the opposite of how most risky items work. Sharp objects, tools, and most sporting goods are fine checked and banned from the cabin. Batteries flip that logic.

A battery fire can be spotted and handled by a flight crew in the cabin. It cannot be handled the same way in an unattended cargo hold. That is the whole reason for the rule.

Laptops, phones, and cameras with a built in battery are generally allowed either way. Loose spare batteries and portable chargers are the ones that get flagged. Check the full rundown on what electronics are allowed in checked bags versus carry-on before you pack.

The 62 inch, 50 pound line almost everyone flies under

Most large US and international carriers set the same free checked baggage allowance. That number is 62 linear inches, meaning length plus width plus height, and 50 pounds per bag. Delta and American both list this exact figure on their own baggage pages.

Where airlines differ is how they punish a bag that breaks the line. Ultra low cost carriers sometimes cap checked bags lower, closer to 40 pounds on some routes. Some international itineraries swap the linear inch rule for a strict piece count instead.

The number that matters is the one your airline lists for your specific route, not the number you remember from your last trip.

Business and first class tickets usually raise the weight ceiling to 70 pounds per bag. That is worth knowing if you are picking a cabin for a heavy trip.

What overweight and oversize actually cost

This is where checked baggage gets expensive fast. Crossing the weight or size line does not add a flat fee, it jumps you into a fee tier. The tier above 50 pounds often costs more than the checked bag fee itself.

American Airlines publishes a tiered structure for domestic flights. Most large carriers mirror the shape of it, even when the exact dollar amounts differ.

Those numbers come from American’s oversize and overweight page, used here as a representative example. Every airline sets its own exact dollar figures. Run your own bag through a baggage fee calculator before you fly rather than guessing, and see our full rundown of checked bag fees by airline for the base prices behind these tiers.

The jump from 50 to 51 pounds can cost as much as an entire second checked bag. That single fact is why a bathroom scale at home earns its keep.

How many bags you get, and which fares give you zero

Basic Economy fares on nearly every major US airline include no free checked bag. You can still pay to check one. The fare class only removes the freebie, it does not remove the option.

Airline credit cards, elite status, and military travel are the most common ways to get a checked bag waived. Outside of those, expect to pay for the first bag on almost every domestic itinerary. Many international carriers still include one or two bags in the base economy fare on international routes.

Compare specific carriers on our airline baggage pages before you assume your old allowance still applies.

What happens after you hand the bag over

Every piece of checked baggage in the United States goes through screening before it gets loaded. This happens whether or not you ever see it happen. Screeners can and do open bags by hand when an image needs a closer look, without you present.

This is where the lock question comes in. A lock that screeners cannot open gets cut off, not worked around. The airline is not responsible for a lock damaged that way.

A TSA recognized lock lets an officer open the bag with a master tool and relock it. That is the only kind of lock that reliably survives the trip. If your bag does get opened, look for a printed notice inside it before you assume something is missing, and if a bag never shows up at all, our guide to lost, delayed, and damaged baggage covers what the airline owes you.

Timing: when to drop the bag, and when it is too early

Most US airlines stop accepting checked baggage 30 to 45 minutes before a domestic departure. International cutoffs are typically closer to 60 minutes. The exact cutoff is set by the airline, and sometimes the airport, not by one national standard.

Arrive after that window and the agent can legally refuse the bag. This holds even if the plane is still sitting at the gate.

Early has a limit too. Many carriers will not tag a bag more than four hours before departure, since there is nowhere in the system to route it yet. Showing up absurdly early does not guarantee an absurdly early bag drop.

If your flight leaves at an odd hour, call the airline rather than assuming.

What travelers get wrong at the counter

The strongest signal from traveler forums is how little slack exists at 50 pounds. People describe getting flagged at exactly 52 pounds, then having to shift items into a coat or a carry-on right at the counter. Nobody reports being let off for a pound or two.

Where there is genuine inconsistency is between bags, not within one. Some agents let you shift weight from an overweight bag into an underweight second bag at the same counter. Others will not, and charge the overweight fee even when your combined weight across two bags would have been fine.

That inconsistency is real. It means the safest plan is packing each bag under the line on its own, not relying on an average across bags.

None of this covers what you can pack in the first place. That depends on the item, not the airline. For rules on individual items, from tools to food to medical gear, use the can I bring it tool rather than guessing from a packing list.

The bottom line

Checked baggage rewards preparation more than almost any other part of a trip. Weigh the bag at home, keep every spare battery in your carry-on, and use a lock TSA can open. Drop the bag inside the airline’s window, not right at the edge of it.

Do that, and the hold stops being a source of surprise fees. It becomes the boring, reliable part of the flight it is supposed to be.