What is the 3-1-1 Rule?

By Nathalie Alonso

Updated July 28, 2017

Colorful toiletries on the cupboard


Packing Like a Pro: Putting Together a TSA-Friendly Liquids Bag

The destination has been chosen. The flights are booked. Now it's time to start packing for your long-awaited family vacation. Whether you're traveling abroad or within the United States, when packing your carry-on luggage, you should have a solid grasp of the guidelines the Transportation Security Administration (TSA) has laid out for taking liquids on commercial flights. It's called the 3-1-1 rule, and, knowing its nuances can help get your family through airport security checkpoints with a lot less hassle.

One Traveler, One Bag

The TSA requires that any liquids in a traveler's carry-on luggage be placed inside a quart-sized re-sealable bag. The pair of 1's in the 3-1-1 rule refers to how many of these “liquids bags” each traveler can carry. It's easy to remember: only one bag per traveler. Because you'll be asked to remove the liquids bag from your luggage and place it in a bin for separate screening, put it toward the top of your carry-on's main compartment or in an outside pocket for quick and easy access.

More Than 3.4 Ounces is a Crowd

The '3' in the 3-1-1 rule is meant to help you remember the maximum size allowed for each item in your liquids bag. No single container may exceed 3.4 ounces. Liquids in containers larger than that can be transported only in checked luggage, even if the bottle or tube is not completely full. If the kids are thirsty, you can purchase drinks after you've passed through the security checkpoint.

A Liquid by Any Other Name

It isn't always immediately obvious what is considered a liquid by the TSA. In this case, anything in the form of a gel, cream, paste or aerosol qualifies as a liquid. Included in that category are products like hairspray, toothpaste, hand sanitizer and body lotion.

Keeping Infants and Toddlers Well-Fed

There are exceptions to the 3-1-1 rule, and an important one applies to liquids you may need to feed your infant or toddler during your flight. You'll be glad to know that you are allowed to carry on more than 3.4 ounces of baby formula, breast milk or juice. While these items will nonetheless be screened by X-ray, you don't need to put them in your liquids bag. Rather, place them in a separate bag and let a TSA agent know you are traveling with these substances before you start the screening process. The same exception also applies to medication in liquid form, whether for children or adults. Expect these items to be tested for explosives.

Tips for Maximizing Space in Your Liquids Bag

While the 3-1-1 rule can seem like an inconvenience, there are ways to make the most of it. Save precious space in your liquids bag by opting for solid versions of toiletries whenever possible. For example, deodorant in solid form does not count toward your liquids bag, whereas gel and aerosol varieties do. If you are inclined to pack body wash, consider a bar soap instead. And rather than carrying travel-sized hair or bath products for each member of the family, considering purchasing full-sized versions once you have arrived at your destination.