TSA 3-1-1 Liquids Rule Explained

The 3-1-1 rule is TSA’s shorthand for its carry-on liquid limits: containers must be 3.4 oz (100 ml) or smaller, all fitting in 1 quart-sized clear bag, and you get 1 bag per person. It applies to liquids, gels, aerosols, pastes, and creams. Here’s what that actually means in practice.

The Transportation Security Administration (TSA) enforces strict limits on liquids, gels, pastes, and aerosols in carry-on baggage. This policy is universally known as the 3-1-1 Liquids Rule.

Understanding exactly how the 3-1-1 rule works before arriving at airport security prevents delays, unnecessary bag searches, and having your personal care items confiscated at the checkpoint.

The 3-1-1 Rule Breakdown

The formula 3-1-1 is an easy way to remember the three key requirements for carry-on liquids:

• 3.4 Ounces (100ml) or Less per Container: All liquids, gels, creams, pastes, and aerosols must be in containers of 3.4 fluid ounces (100 milliliters) or smaller. The container size itself matters—a 6 oz bottle that only contains 2 oz of liquid is still prohibited.
• 1 Quart-Sized Clear Bag: All 3.4 oz containers must fit comfortably inside one clear, quart-sized, resealable plastic bag (approx. 7” x 8” or standard Ziploc quart bag).
• 1 Bag per Passenger: Each traveler is permitted only one liquids bag in their carry-on luggage.

What Counts as a Liquid Under TSA Rules?

TSA considers anything that can be spilled, poured, sprayed, smeared, or squeezed as a liquid or gel. Common items subject to the 3.4 oz limit include:

• Toiletries: Shampoo, conditioner, liquid body wash, perfume, cologne, lotion, sunscreen, liquid foundation, and hair spray.
• Toothpaste & Gels: Toothpaste, styling gel, hair wax, lip gloss, and liquid mascara.
• Food & Drinks: Bottled water, juice, soda, soups, salad dressings, yogurt, salsa, hummus, peanut butter, honey, jams, and Nutella.
• Aerosols: Spray deodorant, hair spray, dry shampoo, and shaving cream.

Critical Exemptions from the 3-1-1 Rule

TSA grants specific exemptions that allow passengers to bring medically necessary liquids and infant nourishment in quantities exceeding 3.4 oz:

1. Medically Necessary Liquids

• Prescription liquid medications and non-prescription liquid medicines (e.g., cough syrups, contact lens solution, saline solution).
• Insulin, EpiPens, and blood/plasma products.
• Frozen ice packs or gel packs used to keep medications cool.
• Procedure: Inform the TSA officer at the beginning of the screening line and place medical liquids in a separate bin.

2. Baby Formula, Breast Milk & Juice

• Infant formula, pumped breast milk, toddler drinks, and baby food pouches are exempt from the 3.4 oz limit.
• You do not need to be traveling with your infant to carry breast milk or baby formula.
• Ice packs, freezer packs, and frozen gel packs used to cool baby food/milk are also permitted regardless of size.

Liquids in Checked Baggage

If you have full-sized liquid bottles, drinks, or toiletries exceeding 3.4 oz (100ml), pack them securely in your checked baggage.

• Most non-hazardous liquids (e.g. shampoo, lotions, water, non-alcoholic beverages) have no TSA quantity limit in checked luggage.
• For alcoholic beverages:
  • Under 24% ABV (beer, wine): No TSA federal volume limit.
  • Between 24% and 70% ABV (spirits/liquor): Up to 5 liters (1.3 gallons) per passenger in unopened retail packaging.
  • Over 70% ABV (140 proof): Prohibited in both carry-on and checked bags due to flammability.

Step-by-Step Checkpoint Packing Tips

1. Pre-pack at Home: Place all 3.4 oz toiletries in your clear quart bag before arriving at the airport.
2. Easy Accessibility: Pack the quart bag near the top of your carry-on or in an exterior compartment so you can quickly remove it at older X-ray scanners.
3. CT Scanners (Newer Machines): At many modern airport checkpoints equipped with computed tomography (CT) scanners, officers will instruct you to leave liquids and laptops inside your bag. Always follow local checkpoint instructions.

CT Scanner Technology and the Future of the 3-1-1 Rule

One of the most significant developments in airport security is the widespread deployment of computed tomography (CT) scanners at TSA checkpoints across the United States. CT scanners create detailed 3D images of bag contents, allowing officers to distinguish between harmless and potentially dangerous liquids with far greater accuracy than traditional 2D X-ray machines.

As of 2026, CT scanners have been installed at hundreds of major U.S. airport security lanes, including high-volume hubs like Los Angeles International (LAX), Hartsfield-Jackson Atlanta International (ATL), and Chicago O’Hare International (ORD). At checkpoints equipped with CT technology, TSA officers may instruct passengers to leave their liquids bag and electronics inside their carry-on bag rather than removing them — the opposite of what travelers have done for nearly two decades.

What this means for your trip:

• Follow the checkpoint signage: Each checkpoint will post instructions indicating whether liquids need to be removed.
• The 3.4 oz limit still applies at CT checkpoints: Even if you don’t remove your liquids bag from your carry-on, the individual container size limit of 3.4 oz (100ml) is still enforced. If officers detect a suspect oversized container in the CT scan, your bag will be physically searched.
• CT scanners are not universally installed: Many regional airports, smaller security lanes, and TSA PreCheck lanes in certain airports still use traditional 2D X-ray equipment. Always be prepared to remove your liquids bag if in doubt.

International Airports and Liquid Rules Outside the United States

The 3-1-1 rule originated in the United States after the 2006 liquid explosives plot, but most countries have adopted similar restrictions. However, important differences exist:

• United Kingdom: The UK is in the process of rolling out advanced CT scanners at major airports like London Heathrow (LHR) and London Gatwick (LGW). Once fully deployed at those lanes, the existing 100ml limit may be relaxed. Travelers should check the latest UK government guidance before departure.
• European Union: EU airports follow the same 100ml / 1 liter bag standard, though individual member states are also advancing CT scanner rollouts at their hub airports.
• Canada: Transport Canada enforces an identical 100ml limit with a 1-litre clear resealable bag requirement.
• Australia: The Australian Border Force follows 100ml per container rules with the same bag requirements.

If you are connecting through multiple countries on a single itinerary, remember that you must clear security again at your connection airport. Liquids purchased airside (past security) at one airport may be confiscated at your connection if they exceed 100ml, particularly on international connections. Always store duty-free liquid purchases in sealed, tamper-evident bags with the airport receipt attached.

Most Commonly Confiscated Liquid Items at TSA Checkpoints

Year after year, TSA publishes data on the most frequently confiscated carry-on items. Understanding this list helps you avoid losing your favorite products at the checkpoint:

1. Full-Sized Shampoo & Conditioner Bottles: Travelers habitually reach for their regular 12 oz or 16 oz bathroom bottles without transferring them into travel-sized containers.
2. Peanut Butter, Nutella & Nut Butters: Despite feeling solid, these spreadable foods are classified as gels under TSA rules and must comply with the 3.4 oz limit.
3. Water Bottles Filled Before Security: Reusable water bottles are completely allowed — but only if empty when passing through the checkpoint. Fill them at water refill stations located past security.
4. Duty-Free Purchases in Non-Compliant Packaging: Perfume or wine purchased duty-free that is not in a sealed, tamper-evident bag from the retailer.
5. Snow Globes: Snow globes contain liquid and are only permitted if the liquid portion is estimated to be 3.4 oz or less. Large decorative globes are regularly confiscated.
6. Yogurt, Applesauce & Pudding: These common snack items are considered gels and must adhere to the 3.4 oz rule in carry-on baggage.

Smart Alternatives to Packing Liquid Toiletries

Many experienced travelers have shifted entirely to solid or solid-format alternatives to avoid the 3-1-1 rule on carry-on-only trips:

• Shampoo Bars & Conditioner Bars: Solid shampoo bars produce the same lather as liquid shampoo with zero liquid volume. They are allowed in carry-on bags in any quantity and never counted toward your quart bag allowance.
• Solid Cologne & Perfume Sticks: Wax-based or solid balm colognes and perfumes are classified as solids and completely exempt from the liquid rule.
• Toothpaste Tablets: Chewable toothpaste tablets — compressed powder tablets you chew and brush with — are TSA-friendly alternatives to toothpaste tubes.
• Solid Deodorant Sticks: Traditional stick deodorant is not subject to the 3-1-1 rule. Switch from spray or gel deodorant to a stick format for carry-on travel.
• Powder Sunscreen: Mineral powder sunscreen provides UV protection without occupying precious liquid bag space.
• Dry Shampoo Powder: Powder dry shampoo (not aerosol spray cans) bypasses the 3-1-1 rule entirely.

Switching just your shampoo and conditioner to bar format can free up significant room in your quart bag for other essentials like toothpaste, sunscreen, and prescription liquids.

TSA PreCheck, Global Entry & the 3-1-1 Rule

Enrollment in expedited screening programs like TSA PreCheck, Global Entry, or CLEAR does not exempt you from the 3-1-1 liquids rule. Regardless of your trusted traveler status:

• You still must comply with the 3.4 oz per container limit in carry-on bags.
• You are still limited to one quart-sized bag of liquids per person.
• The primary benefit of PreCheck in relation to liquids is that at traditional X-ray lanes, TSA PreCheck members typically do not have to remove their liquids bag or shoes, making the screening line faster — but the underlying liquid volume rules remain identical.
• If you enroll in Global Entry (which includes TSA PreCheck), your expedited re-entry processing through U.S. Customs does not affect TSA’s liquids rules for departing flights.

Frequently Asked Questions

Can I bring a full-size bottle of sunscreen in my carry-on? No. Even sunscreen must be in a container of 3.4 oz (100ml) or less to go in your carry-on quart bag. Purchase a travel-size sunscreen or decant a portion into a reusable travel bottle before departing.

Does perfume count as a liquid? Yes. Perfume, cologne, and all fragrance sprays are liquids and must follow the 3.4 oz rule in carry-on bags. Larger bottles should be placed in your checked luggage.

Can I bring multiple quart bags of liquids? No. TSA permits only one quart-sized clear bag per passenger, regardless of how many carry-on bags you bring. Items in a second bag will be confiscated.

Do dry shampoo aerosol cans count as liquids? Yes. Aerosol cans — including aerosol dry shampoo — are subject to the 3.4 oz rule in carry-on bags. Non-aerosol powder dry shampoo is not classified as a liquid and has no volume restriction.

What happens if I accidentally bring an oversized bottle through security? A TSA officer will ask you to either surrender the item, transfer it to checked baggage (if there is time before departure), or return to the ticketing area. Items are never returned once surrendered at the checkpoint.