The 3-1-1 liquids rule limits carry-on liquids to 3.4-oz containers inside one quart-size bag, with one bag per traveler.
Airline checkpoints move quicker when you know limits on liquids, gels, creams, pastes, and aerosols. This guide breaks the rule into plain steps, shows edge cases, and offers a pack list you can use on your next trip.
3-1-1 Liquids Rule Basics
At screening, each container in your liquids kit must be 3.4 ounces (100 milliliters) or less. All those containers need to fit in a single, clear, zip-top quart bag. Each passenger may place only one such bag in a bin. That’s the whole idea in three numbers: 3.4, 1 bag, 1 person.
Security officers need a clean view of your items, so pull the bag out of your carry-on and place it in a tray. Keep the cap tight on every bottle to avoid leaks. Swap bulky bottles for travel sizes, or decant into leak-proof minis. For the full standard, see the TSA liquids rule.
What Counts As A Liquid Or Gel
Think of anything that pours, smears, spreads, pumps, or sprays. That includes water, juice, shampoo, hair spray, lotion, sunscreen, toothpaste, lip gloss, hand sanitizer, soup, sauces, and soft cheese. If it moves like a fluid or paste, pack it in your quart bag unless it meets an exemption.
Quick Carry-On Decisions
Use this table within minutes of packing. It covers the most asked items and how the 3-1-1 limits apply at the checkpoint.
| Item | Carry-On Rule | Notes |
|---|---|---|
| Toothpaste | 3.4 oz or less in quart bag | Travel tube sizes fit best |
| Shampoo/Conditioner | 3.4 oz or less in quart bag | Use refillable minis |
| Lotions/Creams | 3.4 oz or less in quart bag | Check large pump bottles |
| Hand Sanitizer | 3.4 oz in quart bag | The 12 oz waiver ended; stay under 3.4 oz |
| Aerosol Deodorant/Hair Spray | 3.4 oz can in quart bag | Non-toiletry aerosols get different rules |
| Perfume/Cologne | 3.4 oz bottle in quart bag | Seal caps to prevent leaks |
| Makeup (liquid) | 3.4 oz or less in quart bag | Include mascara, liquid foundation |
| Makeup (solid) | Outside the bag | Sticks and pressed powders are fine |
| Food Spreads | 3.4 oz or less in quart bag | Peanut butter counts as a spread |
| Bottled Water | Not allowed past screening | Buy after security |
| Baby Formula/Breast Milk | Exempt from size cap | Declare and remove for screening |
| Medications (liquid) | Exempt in reasonable amounts | Declare and separate at screening |
| Duty-Free Liquids | Allowed in STEB | Must remain sealed with receipt |
| E-cig Liquid | 3.4 oz or less in quart bag | Check airline battery policy |
| Snow Globes | Small ones under 3.4 oz in bag | Larger ones go in checked bags |
Pack A Compliant Quart Bag
Pick a clear, resealable quart-size pouch. A rigid cube pouch looks neat, but a soft zipper pouch bends around bottles and squeezes in more. Lay bottles upright, keep nozzles closed, and use tape on flip caps. Slip the pouch in an outer pocket so you can reach it fast in line.
Smart Container Choices
Buy travel bottles labeled at 3 ounces or 100 milliliters. Wide-mouth minis make refills easy, and silicone walls resist cracks. Set a small funnel next to your sink a day before travel and decant only what you’ll use. Label each bottle. Clear labels help officers read contents without extra questions.
Items You Can Keep Outside The Bag
Solid soap, solid deodorant sticks, solid fragrance balms, wax-based lip balm, pressed powders, makeup wipes, and facial wipes can ride outside the quart pouch. Pack sharp tools and full-size liquids in checked luggage instead of pushing your luck at the belt.
Exceptions That Let Larger Liquids Through
Two broad carve-outs exist: medical needs and infant feeding. Bring only what you need for the flight and any reasonable layover. Tell the officer you’re carrying these items, pull them out early, and expect extra screening like a quick swab. Keep items in their original packaging if you can. For health needs, the agency explains the rules on its medically necessary liquids guidance.
Medical Liquids, Gels, And Aerosols
Larger volumes for health needs are allowed in carry-on when they are needed during travel. This includes saline, contact lens solution, liquid meds, gel packs to chill meds, and nutritional supplements used as treatment. Pack them close to the top of your bag. Place them in a separate bin when asked, and carry a simple doctor’s note if your item might raise questions.
Infant And Child Feeding
Breast milk, formula, toddler drinks, and baby food in jars or pouches are allowed in bigger sizes. Parents may bring ice packs and gel packs to keep these items cool. Tell the officer at the start of the screening process. If you use a cooler bag, open it so the contents can be seen quickly.
Duty-Free Purchases In STEBs
Liquor, perfume, and similar items bought after security at an overseas airport can pass a U.S. connection when they remain in a sealed, tamper-evident bag with the receipt. Do not open the bag before your last landing in the United States. If you open it, the larger bottle will be treated like any other oversize liquid at the next checkpoint.
Toiletry Aerosols And The Line Between Allowed And Forbidden
Small spray cans that count as toiletry items, such as hair spray or spray deodorant, follow the same 3.4 ounce limit in your quart pouch. Non-toiletry aerosols like spray paint are banned from the cabin. Many of those are not allowed in checked bags either. Read the label. When a can lists flammable contents and it isn’t a toiletry article, leave it at home or buy at your destination.
Carry-On Liquids Strategy That Saves Time
Plan your liquids around your arrival. Buy water after security, not before. Rely on hotel toiletries for bulk items. Lean on solid formats where you can. A bar shampoo, a solid sunscreen stick, or solid fragrance frees up space in the quart pouch. Refill small bottles on longer trips instead of packing multiples.
Swap Liquids For Solids
Trade face wash for a solid bar, perfume for a solid balm, and sunscreen for a stick. These swaps lighten your pouch and keep spills away from clothes. Stow razor blades in checked bags and keep your carry-on neat with a small dopp kit that stands upright in a tray.
Move Corner Cases To Checked Bags
Large jars of hair mask, jumbo sunscreen tubes, full-size mouthwash, canned mousse over 3.4 ounces, and large jars of nut butters will all stall your screening. Shift them to checked luggage. If you don’t plan to check a bag, buy at your destination and share within your group.
Common Problems And Fast Fixes
Cap leaks, missing quart bags, and oversize bottles create stress right at the belt. Zip bottles in a small secondary pouch inside the quart bag to trap leaks. Keep one spare quart bag in a side pocket. If a souvenir bottle puts you over the size cap, hand it to a travel buddy who has space in a checked suitcase or ship it home.
When Officers Pull Items For A Closer Look
An officer may set your bag aside to test a liquid. This is routine. Keep calm, answer short, and follow directions. If the test requires opening a sealed item, you can ask to keep it sealed and surrender it, or accept the open test. Plan ahead for that choice on items like high-end perfume.
Rules By Scenario: What To Pack And What To Do
These quick scenarios show what passes without delay and what needs a change. Use them before you print your boarding pass.
| Scenario | Action | Why It Works |
|---|---|---|
| Weekend carry-on only | Decant shampoo, lotion, sunscreen into 3 oz minis and group in one quart bag | Everything fits rules and scans fast |
| Parent with infant | Pack milk, formula, and purees; declare and separate at the belt | Size cap does not apply to feeding needs |
| Traveler with liquid meds | Carry labeled meds and gel packs near top of bag; declare when you reach the officer | Medical items are allowed in larger amounts |
| Connecting from overseas with duty-free | Keep the STEB sealed with receipt until final arrival | Sealed bags permit larger bottles through connections |
| Beauty kit with aerosol hair spray | Use a 3.4 oz can in the quart pouch | Toiletry aerosols follow the same limit |
| Carry-on includes peanut butter jar | Pack single-serve cups in the quart pouch or move jar to checked bag | Spreads count as liquids at screening |
| Souvenir snow globe | Buy a small globe under 3.4 oz and place it in the quart pouch | Small globes pass when bagged |
| Sport spray like WD-40 | Leave at home or ship | Non-toiletry aerosols are not allowed |
Carry-On Prep Checklist
Set your kit the night before travel. Use this short list to avoid delays in the line.
Pack It Right
- All bottles 3.4 ounces or less
- Everything fits in one clear quart bag
- Bag rides in an easy-reach pocket
- Solid items packed outside the bag
Flag The Exceptions
- Medical liquids and gel packs gathered near the top of your bag
- Infant feeding items ready to declare
- STEBs sealed and receipts handy on connections
Where The Official Rules Live
You can always check the agency’s page that explains the liquids rule and the page for medical liquid exceptions. Both pages are kept current by the screening authority.
Wrap-Up: Pack Small, Declare Exceptions, Keep Moving
The fastest flyers keep a prebuilt pouch, swap liquids for solids, and stage any larger exempt items for a quick check. With that routine, you’ll clear security with less stress and more time at the gate.