TSA Liquids Rule Explained: Everything Carry-On Travelers Need to Know
By ChoosePack | Helping travelers master one-bag and carry-on only travel through a proven packing system Last updated: April 8, 2026
The TSA liquids rule is one of the most searched and most misunderstood regulations in air travel. Every carry-on traveler has watched someone ahead of them in the security line lose a full-size bottle of shampoo to the bin. Maybe you have been that person. It is not just annoying. It wastes money, eats time, and it is completely avoidable once you understand how the rule actually works.
This guide covers the rule itself, what counts as a "liquid" (the list is wider than you think), which items are exempt, whether anything changed in 2026, and how to build a carry-on toiletry setup that clears security without a second glance. That last part is where most guides stop short. At ChoosePack, packing to the rule is not a suggestion. It is built into our carry-on packing framework.
What Is the TSA 3-1-1 Liquids Rule?
The TSA 3-1-1 rule governs every carry-on bag passing through a U.S. airport security checkpoint. Each number stands for a specific limit:
- 3.4 ounces (100 milliliters): The maximum size of each individual container.
- 1 quart-size bag: All liquid containers must fit inside a single clear, resealable bag roughly 7 by 8 inches.
- 1 bag per passenger: Each traveler gets exactly one quart bag. No exceptions, no bonus bags.
In practice, a standard quart bag fits around seven or eight travel-size bottles depending on their shape. That is your entire liquid allowance for carry-on.
"The number-one gotcha most travelers miss: TSA evaluates the container size, not the amount of liquid inside. A 6-ounce bottle with just 1 ounce left will still be confiscated. The container itself must be 3.4 ounces or smaller. This single misunderstanding causes more lost products at checkpoints than almost any other mistake. Always check what is printed on the bottle, not what is left inside it."
For the official wording, see TSA's 3-1-1 liquids rule page.
Why Does the Rule Exist?
The 3-1-1 rule was introduced in 2006 after authorities disrupted a transatlantic plot to smuggle liquid explosives onto commercial flights disguised inside ordinary drink bottles. Initially, all liquids were banned from carry-on bags entirely.
Within weeks, TSA worked with national laboratories and international agencies to determine a volume threshold below which liquid threats posed minimal risk. The result was 3-1-1, announced on September 26, 2006. The 3.4-ounce figure is not random. It is the direct conversion of 100 milliliters, the international standard set by ICAO so that the rule would align across countries.
Understanding the origin helps explain why the threshold has not budged in nearly 20 years: the science behind it has not changed.
What Counts as a "Liquid" Under TSA Rules?
This is where most packing mistakes happen. TSA defines "liquid" much more broadly than everyday language does. If a substance flows, spreads, squeezes, smears, sprays, or pours, it falls under 3-1-1. That includes gels, creams, pastes, aerosols, and plenty of items people do not think of as liquids.
A good rule of thumb from our experience at ChoosePack: hold the container upside down. If the contents move at all, even slowly, treat it as a liquid.
Quick-Reference Table: Liquid vs. Not Liquid
Items That Surprise Most Travelers
A few that catch people off guard:
- Food is a big one. Peanut butter, hummus, and jams are among the most commonly confiscated items at checkpoints according to TSA.
- Gel ice packs that are not frozen completely solid are treated as liquids.
- Snow globes fall under the rule because of the liquid inside.
- Lip gloss and liquid lipstick count, even though solid lipstick does not.
- Aerosol dry shampoo counts. Powder dry shampoo does not.
When in doubt about a specific item, search it on the TSA "What Can I Bring?" tool before you leave home.
What Liquids Are Exempt from the 3-1-1 Rule?
Several categories can exceed 3.4 ounces in carry-on. Each has specific conditions:
Medically necessary liquids. Prescription medications, over-the-counter liquid medicines, and contact lens solution (classified by TSA as OTC medication) may exceed 3.4 ounces. Declare them to the officer at the start of screening. Original labels help but are not always required. For full details, see TSA's guidance on medical liquids.
Baby and child nourishment. Formula, breast milk, toddler drinks, and baby food are all exempt from the size limit and do not need to fit inside your quart bag. Ice packs and freezer packs to keep them cool are also allowed. One detail most guides miss: breast milk is permitted even if you are not traveling with a child.
Duty-free international purchases. Liquids bought at international duty-free shops may exceed 3.4 ounces if they are sealed in a tamper-evident bag by the retailer, purchased within 48 hours, and accompanied by the original receipt. This only applies when connecting through a U.S. airport from an international origin. See TSA's duty-free liquids policy for the exact conditions.
For everything outside these categories, the 3.4-ounce limit holds firm. That is why a smart packing approach matters more than memorizing exceptions.
Has the TSA Liquids Rule Changed in 2026?
No. The federal 3-1-1 standard has not changed.
This is the single biggest source of confusion right now, so it is worth unpacking clearly.
Starting in 2023, TSA began deploying Computed Tomography (CT) scanners at select checkpoints. These scanners produce 3D images of bag contents, allowing officers to see more detail without opening bags. At CT-equipped lanes, travelers may be allowed to leave their quart bag inside their carry-on during screening.
Here is what that means and what it does not mean:
- What changed: The screening process at some checkpoints. You might not need to pull your liquids bag out of your carry-on.
- What did not change: The size limits. Every container still must be 3.4 ounces or smaller. The quart-bag requirement still applies.
The confusion gets worse because there is no public list of which specific checkpoints at which airports have CT scanners. Even within a single airport, one lane might have CT while the next one does not. Enforcement is inconsistent.
International headlines add fuel to the fire. Several UK airports, including London Gatwick and Leeds Bradford, allow liquids up to 2 liters at CT-equipped checkpoints. U.S. travelers read those stories and assume the same applies at home. It does not.
Homeland Security Secretary Kristi Noem stated in July 2025 that TSA was "reevaluating the liquids policy." However, no official policy change has followed.
Our recommendation at ChoosePack: Always pack to the 3-1-1 standard. If you happen to pass through a CT lane and do not need to pull out your bag, great. You save 30 seconds. But you never risk losing a product. There is no downside to compliance.
How to Pack Liquids for Carry-On Travel: The ChoosePack Approach
Understanding the rule is step one. Working within it efficiently is what separates a stressed packer from a confident one-bag traveler. This is the 5-step framework we use and teach at ChoosePack.
Step 1: Audit Your Liquid Inventory
Before packing a single bottle, write down every liquid, gel, cream, paste, and aerosol you plan to bring. Face wash, moisturizer, sunscreen, toothpaste, contact solution, deodorant, hair product, lip balm. Most travelers discover their list runs eight to ten items before any optimization. That is already more than a quart bag comfortably holds.
Step 2: Eliminate Through Solid Alternatives
This is the highest-leverage move in carry-on packing. Every liquid you convert to a solid frees a slot in your quart bag:
- Shampoo → shampoo bar
- Conditioner → conditioner bar
- Toothpaste → toothpaste tablets
- Deodorant gel → solid stick
- Sunscreen lotion → solid sunscreen stick
- Body wash → bar soap
- Liquid perfume → solid perfume balm
After this step, most travelers using our packing system reduce their quart-bag contents to just three or four containers. For a deeper breakdown of what we have tested and recommend, see our solid toiletry alternatives guide.
From experience: When we first started building the ChoosePack framework, one of the most common packing audits we ran showed travelers carrying seven or eight liquid toiletries in their quart bag with no room to spare. After switching to shampoo bars, toothpaste tablets, and solid deodorant alone, those same travelers had three open slots. That freed-up space is what lets you carry the liquids you actually cannot replace, like prescription eye drops or a specific moisturizer, without squeezing or leaving things behind.
Step 3: Right-Size Your Containers
Do not default to a 3.4-ounce bottle for everything. If your trip is five days and you use a small amount of moisturizer daily, a 1-ounce container is more than enough. Smaller containers mean more room in the bag and less weight in your carry-on. For help determining what size containers match your trip length, check our one-bag packing checklist.
Step 4: Choose the Right Bag
A quart-size bag measures roughly 7 by 8 inches. There is no such thing as a "TSA-approved" or "TSA-certified" clear bag. That label is marketing, not regulation. Any clear, resealable bag that is approximately quart-sized works, whether it is a disposable Ziploc or a reusable pouch with a durable zipper.
For frequent travelers, a reusable clear bag holds its shape better, resists punctures, and makes it easier to find what you need. We compare popular options in our clear toiletry bag guide.
Step 5: Position for Speed
Pack your quart bag in the top compartment or an exterior pocket of your carry-on so you can grab it in under five seconds at the security belt. Even at CT-equipped lanes, officers sometimes ask to inspect it separately. Being ready keeps the line moving and keeps your screening stress-free.
For a full walkthrough of every step from curb to gate, see our TSA checkpoint guide.
Does TSA PreCheck Change the Liquids Rule?
TSA PreCheck does not change the 3-1-1 liquid size limits. PreCheck travelers may be able to leave their quart bag inside their carry-on during screening, similar to CT-scanner lanes. But the container size limit and one-bag-per-person rule are identical.
CLEAR works differently. It lets you skip the identity verification line, not the X-ray screening. Liquids rules apply fully.
No membership, program, or trusted-traveler status exempts you from 3-1-1.
Key Mistakes That Cost Travelers at the Checkpoint
- Packing a half-empty oversized bottle. Container size is what matters. A 6-ounce bottle with 1 ounce inside gets pulled every time.
- Assuming your airport has CT scanners everywhere. Even airports with CT technology may only have it at certain lanes. If you guess wrong, you lose products.
- Forgetting that food counts. Peanut butter, hummus, yogurt, soup, and jam are all subject to 3-1-1. Solid snacks are not.
- Using an opaque or oversized bag. Officers need to see your liquids at a glance. Clear and quart-sized is the standard.
- Skipping the pre-trip audit. Five minutes of checking container sizes before you leave can save 20 minutes and expensive products at the checkpoint.
- Believing PreCheck or CT scanners remove the size limit. They change how you are screened. They do not change what you can bring.
The Bottom Line
The TSA 3-1-1 liquids rule has not changed since 2006 and it remains the standard you should pack to in 2026. Containers must be 3.4 ounces or smaller, they must fit in one clear quart-size bag, and each passenger gets one bag.
For carry-on-only travelers, the rule is not a limitation. It is a design constraint. Work within it using a system (audit, swap to solids, right-size, choose your bag, position for speed) and you will clear security without losing a single product.
If you are unsure whether a specific item counts, use the TSA "What Can I Bring?" tool or contact AskTSA on X (formerly Twitter), available 365 days a year.
For a broader look at how to fit everything into one bag without checking luggage, start with our complete carry-on packing system. For airline-specific size and weight limits, see our carry-on size guide for every major airline.
That is the ChoosePack approach: a system, not a guess.
Frequently Asked Questions About the TSA Liquids Rule
How many bottles can I bring in my carry-on liquids bag?
There is no set bottle limit. The constraint is that every container must be 3.4 ounces or smaller and all of them must fit inside one quart-size bag (roughly 7 by 8 inches). In practice, most travelers fit around seven or eight standard travel bottles depending on shape and size.
Does toothpaste count as a liquid?
Yes. TSA classifies toothpaste as a gel or paste, which falls under the 3-1-1 rule. Travel-size toothpaste (3.4 ounces or smaller) must go in your quart bag. Toothpaste tablets are a solid alternative that does not count as a liquid and can be packed freely.
Is mascara a liquid according to TSA?
Yes. Mascara is classified as a liquid because of its gel-based formula. It must go in your quart bag. Standard mascara tubes are well under 3.4 ounces, so they fit easily, but they do take up a slot.
Is lipstick a liquid?
Solid lipstick is not considered a liquid and does not need to go in your quart bag. However, liquid lipstick and lip gloss do count as liquids and must follow 3-1-1.
Does deodorant count as a liquid?
It depends on the form. Gel deodorant, spray deodorant, and roll-on deodorant all count as liquids. Solid stick deodorant does not. If you want to keep a quart-bag slot open, solid stick is the way to go.
Can I bring spray sunscreen on a plane?
Yes, but it must be in a container of 3.4 ounces or smaller and placed in your quart bag. Spray sunscreen is treated as an aerosol liquid. Solid sunscreen sticks are a good alternative that does not count as a liquid.
Can I bring medication over 3.4 ounces in my carry-on?
Yes. Medically necessary liquids, including prescription and over-the-counter medications, are exempt from the 3.4-ounce limit. Declare them to the TSA officer at the checkpoint before screening begins. Keeping medications in their original labeled containers helps but is not strictly required. See TSA's medical liquids guidance for full details.
What about baby formula and breast milk?
Formula, breast milk, toddler drinks, and baby food may exceed 3.4 ounces and do not need to fit in your quart bag. Ice packs and freezer packs used to keep them cool are also allowed. Breast milk is permitted even when you are not traveling with a child.
Does my clear bag need to be a specific brand or "TSA-approved"?
No. There is no official TSA certification or approval program for clear bags. Any clear, resealable bag that is approximately quart-sized (about 7 by 8 inches) meets the requirement. A Ziploc works. A reusable clear pouch works. Ignore marketing that claims "TSA-approved" status. For our tested picks, see the ChoosePack clear toiletry bag guide.
Can I bring a water bottle through security?
An empty water bottle is allowed through the checkpoint. Fill it at a water fountain or bottle-filling station on the other side of security. A water bottle containing any liquid will be flagged and you will need to either drink it, pour it out, or surrender it.
Are solid toiletries subject to the 3-1-1 rule?
No. Solid items like bar soap, shampoo bars, conditioner bars, solid deodorant sticks, solid sunscreen sticks, and toothpaste tablets are not considered liquids. They can go anywhere in your carry-on without restriction. This is the core of the ChoosePack approach to maximizing quart-bag space.
Has TSA eliminated the liquids rule in 2026?
No. The federal 3-1-1 rule is fully in effect as of April 2026. CT scanners at some checkpoints may change the screening process (leaving your bag inside your carry-on), but the size limits are identical. Always pack to the 3-1-1 standard.
Does TSA PreCheck change the liquids rule?
No. PreCheck may allow you to leave your quart bag inside your carry-on during screening, but the 3.4-ounce container limit and one-bag-per-person rule still apply. No trusted-traveler program exempts you from 3-1-1.
Do the rules apply to international flights departing from the U.S.?
Yes. The 3-1-1 rule is a federal regulation enforced at all U.S. airport security checkpoints regardless of your destination. If departing from a non-U.S. airport, that country's own rules apply at their checkpoint. Some international airports have more relaxed liquid limits at CT-equipped checkpoints, but those policies do not apply in the United States.
What happens if I bring an oversized liquid container?
The item will be flagged during screening. In most cases, TSA will ask you to surrender it. The container is discarded. You will not be fined or detained for a standard oversized liquid, but you will lose the product and experience a brief delay. To check the current status of any item before you fly, use the TSA's online search tool.
Can I bring duty-free liquids over 3.4 ounces on a connecting flight?
Under narrow conditions, yes. The liquids must have been purchased at an international duty-free shop, sealed in a tamper-evident bag by the retailer, bought within 48 hours, and accompanied by the original receipt. This applies when connecting through a U.S. airport from an international origin. If any seal is broken or conditions are not met, the item will be subject to standard 3-1-1 limits.
Can two passengers share one quart-size bag?
No. Each passenger is allowed one quart-size bag. However, if your bag is full and your travel partner has room in theirs, you can redistribute items between the two bags before reaching the checkpoint. Each person still carries only their own single bag through screening.