All About the 3-1-1 Rule

By Denise Schoonhoven

What is the 3-1-1 rule all about, anyways?

The 3-1-1 Rule might look like secret code, but once you decipher what the three little numbers mean, preparing a carry-on for your next flight is a cinch. Each number stands for a simple step to comply with the official TSA Liquids Rule. It defines how much liquid, gel, cream, paste and aerosols you can take through security screening at the airport. It also tells you how to package the items so they can be properly inspected. You won't need a decoder ring to crack the secret of taking liquids in your carry-on when you follow the numbers.

Measuring up: the “3”

The three is shorthand for 3.4 ounces. Manufacturers of travel-size bottles of shampoo, conditioner, sunscreen and similar products that fall under the TSA Liquid Rule stick with this measurement, which may also be shown as 100 milliliters. While it's handy to purchase products for your trip in miniature containers, always double check the label to make sure it doesn't exceed the 3.4 oz./100 ml limit.

  • Savvy traveler tip: Skip buying pricey travel-size products and pack your regular shampoo and cosmetic items in small containers. You can pick up packages of sturdy plastic 3-ounce bottles and containers with screw-on lids and flip tops at most drug stores. Fill them with your own hair care products, cough syrup, make-up remover, or even the favorite homemade food you might fancy along the way. The containers are reusable, so you'll be set next time you need to hop on a flight. Alternatively, save up shampoo and conditioner samples you may receive from drug or beauty stores and pack those in your carry-on. These one-time-use packets are an easy, disposable solution if you don’t want to invest in three-ounce bottles.

In the clear: the first “1”

One of the 3-1-1 Rule's numbers stands for one-quart, as in a clear, see-through, one-quart plastic bag. It must be resealable; zipper-style closure is best and the most readily available. Whatever fits inside the sealed bag is the limit of what you can take in your carry-on and through security. Yes, you'll have to buy a whole box of the resealable bags to use just one for your carry-on, but the smallest box is usually a 10 count for a fairly small price.

  • Savvy traveler tip: Place the filled, sealed, one-quart bag in your carry-on luggage last, on top of everything else. When it's time to put your bag on the conveyor belt to pass through the security scanner, you'll be able to remove the bag quickly for inspection instead of having to grope around during what can feel like a stressful situation.

All for one: the second “1”

The final number of the 3-1-1 Rule stands for one bag, and one bag only. Any liquid, aerosol or cream-like substance you intend to carry on-board must be in that single, quart-size plastic bag. If you must carry more, it will have to go in your checked luggage.

  • Savvy traveler tip: Many hotels provide personal care amenities such as shampoo, shower gel and lotion. You may be able to fit everything you want in that sole plastic bag if you don't need to pack what's already waiting for use at your destination.

Getting around the 3-1-1

The TSA Liquid Rule is in place for your safety and that of fellow travelers. You may, however, find that substitutions save space and work just as well as liquids and other items covered by the rule.

  • Dry shampoo, a powder that can be combed through your hair, doesn't need to be placed in the 1-quart plastic bag. Neither does tooth powder for keeping your pearly whites clean.
  • Use smaller one- or two-ounce containers for items you won't need much of, such as eye drops and nail polish remover.
  • Switch from foaming shaving cream in a canister to a shaving soap that fits in a small plastic container and makes a great lather when you're ready to freshen up for adventures at your travel destination.

About the Author

Denise Schoonhoven has worked in the fields of acoustics, biomedical products, electric cable heating and marketing communications. She studied at Newbold College and Middlesex Polytechnic in the UK, and Walla Walla University. A writer since 2008, Schoonhoven is a seasoned business traveler, solo tourist, gardener and home renovator.