What is the liquid requirement for flying

Dealing with airport security can be one of the more daunting aspects of air travel, from the detailed rules about what you can and can't bring on board to the long lines that often form at checkpoints.

One rule that frequently trips up travelers is the Transportation Security Administration's (TSA) 3-1-1 regarding liquids in carry-on bags. We're here to walk you through the finer details of the rule and provide helpful tips for packing liquids when you're flying.

What is the TSA's 3-1-1 rule?

In 2006, British security officials thwarted a plot to bomb an aircraft with liquid explosives carried on board. Since then, security agencies around the world have limited the amount of liquid passengers can bring through airport security.

For the TSA, which regulates travel in the United States, all liquids, gels, and aerosols must be in containers that are 3.4 ounces (100 milliliters) or less. All liquids must fit into a single, clear quart-size bag — passengers can only pack one of these bags in their carry-on.

The 3-1-1 designation is a simple way to remember these numbers: individual liquid containers must be 3.4 ounces or smaller, they must fit into one clear, quart-size bag, and there is only one bag allowed per passenger.

Liquids that do not comply with the 3-1-1 rule must be packed in checked bags, or thrown out at airport security. Some liquids, such as gasoline or other flammable liquids, are prohibited entirely, both in checked and carry-on bags. You can find a full list of permitted and prohibited items on the TSA's website.

If you're unsure if a specific item adheres to the 3-1-1 rule, you can always contact the TSA before your trip. "Tweet your questions and comments to @AskTSA or via Facebook Messenger, weekdays from 8 a.m. to 6 p.m. ET," TSA spokesperson Jessica Mayle tells Travel + Leisure. "You can also call the TSA Contact Center at 866-289-9673."

Are there any exceptions to the 3-1-1 rule?

The TSA does exempt some items from the 3-1-1 rule: medically necessary liquids, formula, and breast milk. You can bring more than 3.4 ounces of these liquids on board, but you may have to undergo additional security screening.

"Inform the TSA officer at the beginning of the screening process that you're carrying them," says Mayle. "These liquids are typically screened by X-ray, but TSA officers may also test them separately for explosives or concealed prohibited items. Officers may ask you to open the container and/or have you transfer a small quantity of the liquid to a separate empty container, or dispose of a small quantity, if feasible."

If you don't want your exempt liquids to be screened by X-ray, inform your TSA officer, and they will use alternative security measures to clear the items.

And that's not all. "There's an exception for hand sanitizer, which has a temporary 12-ounce limit," says Mayle. But as COVID-19 travel restrictions and protocols continue to lift, the temporary special case for hand sanitizer could change, too.

Another exception is liquids purchased after security in an airport. In domestic U.S. airports, you can bring nonalcoholic drinks and other liquid items purchased airside onto your flight. (This is not always the case in international airports.) Duty-free liquids, however, will be sealed in a tamper-safe bag before boarding — sometimes they're permitted in the cabin, and other times they may be stowed elsewhere on the plane.

By now, you’ve probably got the whole TSA liquid limit rule down to a science. After all, it’s been more than 15 years since these TSA rules were instated. To recap: All liquids (including gels like toothpaste) and some foods that are considered liquids need to be in separate containers that hold no more than 3.4 ounces. When you go through the airport security check, you’ll have to take them out of your bag and put them in a bin, where they’ll be X-rayed and sometimes additionally inspected. If you have things you shouldn’t, you can toss them or go back to the gate to check them; otherwise, your friendly TSA agent will confiscate them.

But did you know there are certain exceptions to this rule? You should. Here’s what you need to know about the TSA’s liquid limit loopholes so you can bring these items through security and on board with you. But before we dig in, here are a few answers to travelers’ most commonly Googled questions on this topic.

What is the 3-1-1 liquid rule?

It’s the fancy name for the TSA liquid limit rule we mentioned above. The TSA permits you to carry any liquids, gels and aerosols in containers that hold up to 3.4 ounces. It’s called the 3-1-1 rule because your liquids must be no more than 3.4 ounces (that’s the 3), they have to fit into 1-quart bags (there’s the 1) and you’re only allowed one (that’s the final 1) of the bags.

While this TSA carry-on rule may seem arbitrary, it was instated in 2006, after intelligence experts uncovered a transatlantic terrorist plot to detonate liquid explosives on multiple flights. So, while it’s annoying to have to squish your shampoo, makeup, moisturizer, toothpaste and certain foods into tiny containers and put those tiny containers into a quart-sized bag, it’s for your safety. Anything that doesn’t fit these specifications either needs to be left at home or packed in your checked luggage.

How many 3-ounce bottles can I carry on?

You must be able to fit all your 3-ounce bottles into a 1-quart bag, which is 6 x 9 inches. This usually equates to nine bottles. FYI, you can use a Ziploc or any anything that’s about that size, but the TSA doesn’t officially approve or disapprove of any bags.

Do you still have to put liquids in plastic bags in 2022?

Yes, the rule about the bags is still a thing, but the TSA actually doesn’t specify whether that bag needs to be clear. Still, a clear plastic bag will certainly make things easier for your TSA agent and help you get through security faster. If you’ve forgotten to put your items in a bag, it likely won’t be a big deal and you can simply put them in the bin. The main thing is to respect the TSA liquid limit, but following the rules is always a good idea so you don’t need to spend more time than necessary at the security checkpoint.

Image Source/Getty Images

Breast milk, formula and baby food

This has long been a concern for moms of little ones, and chances are, you’ve heard a few airport horror stories about passengers being forced to dump these items at the security checkpoint. The key to avoiding a similar hassle? Knowing the TSA’s actual rules—and printing them out and carrying them with you, just in case. Breast milk, formula and baby food, regardless of size, are exempt from the TSA liquid limit rule and are allowed in your carry-on.

One caveat: These liquids are permitted only in “reasonable quantities,” though the TSA doesn’t specify further. So if you have a lot, pack what you need for the flight, and then check or ship the rest. Also be aware that a TSA agent will likely swab the container to check for explosives. But don’t worry—the swab won’t actually touch the contents.

Does toothpaste count as a liquid?

How much liquid can you take on a plane in checked baggage 2022?

How many 100ml bottles can you take on the plane?

Do liquids have to be in a Ziploc bag when flying?