I learned the 3-1-1 rule the hard way at 5 a.m. on a flight to Denver. A full-size tube of toothpaste cost me fifteen minutes at the checkpoint and a sprint back to the trash. Since then, I’ve packed over 200 carry-on bags without losing a single item to TSA. Here’s everything you need to know about how to pack a carry-on that passes TSA’s 3-1-1 liquids rule without getting items confiscated.
The TSA 3-1-1 rule allows each passenger to bring liquids, gels, aerosols, creams, and pastes in containers of 3.4 ounces (100 milliliters) or smaller, all packed into one clear, quart-sized, resealable plastic bag, with one bag per person. Understanding this regulation is the single most important step to passing security smoothly.
Table of Contents
What Is the TSA 3-1-1 Rule and Why Does It Exist
The 3-1-1 rule is a TSA security regulation that limits how much liquid you can carry through airport security checkpoints. The name itself is a memory device: 3 ounce containers, 1 quart-sized bag, 1 bag per passenger.
Breaking Down the 3-1-1 Numbers
Each number in the rule maps to a specific, measurable requirement. The “3” refers to the maximum container size of 3.4 ounces (100 milliliters). The first “1” refers to the single quart-sized clear plastic bag. The final “1” refers to one bag per passenger.
TSA measures container size by the printed capacity on the label, not by how much liquid is actually inside. That means a 4-ounce bottle that’s only half full still violates the rule. This is one of the most common mistakes travelers make.
Why the Rule Exists
The 3-1-1 rule was implemented in 2006 after British security services uncovered a plot to smuggle liquid explosives onto transatlantic flights. Limiting liquid quantities reduces the risk of certain threats and allows X-ray machines to screen carry-on bags more effectively.
More than two decades later, the rule remains the foundation of airport security liquid screening. Even with new CT scanners rolling out at major U.S. airports, the 3-1-1 framework still applies in 2026 and is unlikely to change in the near future.
What Counts as a Liquid Under TSA Rules
TSA defines liquids broadly. Anything that is pourable, spreadable, squeezable, or semi-solid at room temperature generally counts as a liquid. This includes obvious items like shampoo and water, plus many products travelers don’t expect to be regulated.
Surprising Items That Count as Liquids
- Toothpaste – yes, even travel-sized tubes must go in the quart bag
- Mascara – the wet formula triggers liquid rules
- Lip balm and chapstick – the soft, semi-solid texture qualifies
- Foundation and liquid foundation – all liquid foundations must be in the quart bag
- Hand sanitizer – temporarily allowed up to 12 ounces during COVID, but back to 3.4 oz under current rules
- Peanut butter, jam, and hummus – spreads count as liquids
- Wet wipes – if they contain liquid lotion, they count
- Contact lens solution – always in the quart bag
Items That Don’t Count as Liquids
- Solid deodorant (sticks or crystals)
- Powdered makeup and pressed powders
- Solid bar soap and shampoo bars
- Lipstick (solid stick form)
- Tooth powder and crystal deodorant
- Dry snacks like crackers and cookies
- Solid medications and pills
The dividing line is simple: if the item can be poured, squeezed, or smeared at room temperature, it goes in the quart bag. If it holds its shape, it’s typically fine to pack anywhere in your carry-on.
Container Size Requirements Explained
The container size limit is the most strictly enforced part of the 3-1-1 rule. TSA officers pull out sample containers and check the printed volume, not what’s inside.
Why Container Size Trumps Content Amount
TSA uses the printed container size as the official measure because security needs clear, consistent rules. A 4-ounce bottle that contains 2 ounces of liquid still has the capacity to hold more. Security officers don’t have time to measure contents at the checkpoint, so they go by what’s printed on the label.
If you bring a 4-ounce bottle, even half empty, the officer will likely confiscate it. I learned this from experience on a flight from Chicago when my half-empty conditioner bottle was tossed in the bin.
How to Measure Your Containers
Check the label on the bottom or back of each container. The volume is usually printed in fluid ounces (fl oz) or milliliters (ml). The limit is 3.4 ounces or 100 milliliters. Containers labeled “3 oz” or “1 oz” or “50 ml” are compliant. Anything labeled “4 oz” or “120 ml” is not, regardless of how much is inside.
Refillable travel bottles are a smart solution. Buy one set of TSA-compliant containers, label them with a permanent marker, and refill them from your full-size products at home. This saves money and reduces waste over time.
Quart-Sized Bag Rules and What Actually Fits
The quart-sized bag requirement trips up more travelers than any other part of the rule. The official TSA guidance is a 1-quart (approximately 1 liter) clear, resealable plastic bag. Standard zip-top bags sold in grocery stores as “quart” or “sandwich” size work fine.
The Quart-Sized Bag Specification
The bag must be clear (transparent), resealable (zip-top), and approximately 1 quart in capacity. TSA does not require branded TSA-approved bags. A plain sandwich-size zip-top bag works as well as a $15 specialty bag.
The bag must fit comfortably in your carry-on, typically near the top so you can remove it easily at the checkpoint. Each passenger gets one bag. If you’re traveling with family, each person needs their own quart bag.
How Many 3.4 oz Bottles Can You Fit
A standard quart-sized bag holds roughly 6 to 10 travel-sized bottles, depending on their shapes. Slim, rectangular bottles pack more efficiently than round ones. Through dozens of packing tests, I’ve found that 7 to 8 bottles is the realistic maximum for a comfortable fit.
For travelers who need more space, the answer is solid alternatives or checked baggage. There’s no way to fit a full-size beauty routine in one quart bag. Plan ahead and prioritize what you absolutely need for the trip.
Step-by-Step Packing Process That Passes Every Time
After packing hundreds of carry-on bags, I developed a simple 5-minute method that works every time. Here’s the exact process I use before every flight.
Before You Pack: Gather Your Supplies
- One quart-sized clear zip-top bag
- All travel-sized liquids (3.4 oz / 100 ml or smaller)
- Tweezers and small scissors (under 4 inches, packed separately)
- Solid toiletries as backups (deodorant, bar soap)
- Any prescription medications in original labeled containers
The 5-Minute Packing Method
Step 1: Lay out all liquids on your bathroom counter. Check each container for the printed volume. Remove anything that exceeds 3.4 oz (100 ml).
Step 2: Place the largest, flattest bottles at the bottom of the quart bag. This is usually shampoo and conditioner.
Step 3: Add medium-sized bottles like face wash and lotion into the gaps.
Step 4: Tuck small items like lip balm, mascara, and travel-size toothpaste into remaining spaces.
Step 5: Seal the bag and press out excess air. The bag should lie flat with all items visible.
Step 6: Place the quart bag at the top of your carry-on for easy access at the checkpoint.
At the Checkpoint: What to Expect
When you reach the security checkpoint, remove the quart-sized bag from your carry-on and place it in a separate bin for X-ray screening. TSA requires this for every passenger, including those with TSA PreCheck.
You’ll also need to remove laptops, tablets, and any large electronics. Liquids in your quart bag go through the same X-ray machine as your other carry-on items. Newer CT scanners can see liquids in 3D, but the bag still needs to come out of your luggage.
TSA 3-1-1 Rule Exemptions You Should Know
Some items are exempt from the 3-1-1 rule. Knowing these exemptions can save you real hassle, especially for medical needs and family travel.
Prescription Medications and Medical Necessities
Prescription medications in liquid form are allowed in carry-on bags in quantities larger than 3.4 oz. TSA requires that medications be labeled with the passenger’s name and the prescription, but they don’t need to fit in the quart bag.
Medical devices like insulin pumps, EpiPens, and liquid nutrition are also exempt. Notify the TSA officer at the start of the screening process if you have these items. They may require additional screening but will not be confiscated.
Infant and Toddler Food and Milk
Formula, breast milk, and baby food are exempt from the 3-1-1 rule for travelers flying with infants. You can bring reasonable quantities for the duration of the flight, even in containers larger than 3.4 oz.
These items must be declared to the TSA officer at the checkpoint and may be subject to additional screening. Ice packs used to keep baby food cold are also allowed through security if they are partially frozen at the time of screening.
Duty-Free Liquids from International Flights
Liquids purchased at duty-free shops after the security checkpoint, or in international airports, can be brought on the plane in containers larger than 3.4 oz. The shop must seal the items in a tamper-evident bag with the receipt inside.
If you have a connecting flight in the U.S., the liquids must remain in the sealed bag. Opening the bag at any point triggers the 3-1-1 rule, and the items will be confiscated at the next checkpoint.
Common Mistakes That Get Items Confiscated
After talking to TSA officers and reading hundreds of traveler forum posts, I’ve identified the most common mistakes that lead to confiscation. Avoid these, and you’ll pass through without issues.
Mistake 1: Using the Wrong Type of Bag
A washable toiletry bag, even if it’s clear, doesn’t meet TSA requirements. The bag must be resealable, which means a zip-top closure. TSA officers will sometimes allow these, but more often they’ll ask you to transfer items to a proper zip-top bag, which slows you down.
Many travelers on Reddit have shared that they’ve had toiletry bags rejected because the zipper was not a clear zip-top. Play it safe and use a standard sandwich-size zip-top bag.
Mistake 2: Forgetting About Semi-Liquid Items
Toothpaste, deodorant cream, mascara, and lip balm all count as liquids. Forgetting these is the most common reason people get items confiscated. A forum comment from a frequent flyer said they lost a $20 tube of fancy toothpaste because they forgot to put it in the quart bag.
Walk through your bathroom routine mentally before packing. Anything you apply wet or wet-like goes in the quart bag.
Mistake 3: Overpacking the Quart Bag
TSA allows one quart-sized bag per passenger, not per trip length. For a 10-day trip, you still only get one bag. The bag must seal completely flat. If it bulges, an officer may ask you to repack or remove items.
Multiple travelers have reported that overstuffed bags led to additional screening or delays. Pack only what you need for the trip and consider alternatives for anything that doesn’t fit.
Smart Alternatives: Non-Liquid Toiletries for Travel
The easiest way to beat the 3-1-1 rule is to skip liquids altogether. Solid and powder alternatives have come a long way and work well for travel.
Solid Bar Alternatives
- Shampoo bars – work like regular shampoo but in solid form
- Conditioner bars – effective for most hair types
- Body wash bars – last longer than liquid equivalents
- Solid lotion bars – moisturize without a bottle
- Solid perfume – compact and TSA-friendly
Powder and Tablet Substitutes
- Tooth powder or tablets – no liquid restrictions
- Dry shampoo powder – absorbs oil without liquid
- Crystal deodorant – solid stick form, no liquid issues
- Face wash bars – similar to soap but formulated for skin
These solid alternatives don’t count as liquids and can go anywhere in your carry-on. They’re also lighter and more compact than liquid versions, which is a win for travelers trying to pack light.
2026 Updates and What Travelers Should Know
The 3-1-1 rule has remained largely unchanged for two decades, but technology and enforcement continue to evolve. Here’s what travelers should know in 2026.
Current 2026 Enforcement
As of 2026, the 3-1-1 rule is fully enforced at all U.S. airports. Travelers are still required to bring liquids in containers of 3.4 oz or smaller, in a single quart-sized clear bag. The rule applies to all passengers, including those with TSA PreCheck and Clear memberships.
CT scanners are now installed at over 200 U.S. airports. These new machines can identify liquids without requiring them to be removed from your bag in some cases. However, TSA still recommends placing your quart bag in a separate bin for faster screening.
Future of Liquid Screening Technology
Several pilot programs are testing new liquid screening technology that could eliminate the 3-1-1 rule entirely. These systems use advanced sensors to detect liquid threats in real time, regardless of container size.
For now, expect the 3-1-1 rule to remain in place at least through the next few years. Until the technology is widely deployed, your best bet is to pack properly using the guidelines above.
Frequently Asked Questions
Can I have 2-3 ounces of liquids in a carry-on bag when flying?
Yes, you can bring liquids in containers of 3.4 ounces (100 milliliters) or smaller in your carry-on bag. All containers must fit inside a single clear, quart-sized, resealable plastic bag. The amount of liquid inside the container doesn’t matter as long as the printed container size is 3.4 oz or less. Larger containers, even if partially empty, will be confiscated at the security checkpoint.
Does toothpaste have to go in a 3-1-1 bag?
Yes, toothpaste is classified as a liquid by TSA and must go in your quart-sized clear bag. This applies to all forms of toothpaste, including gel, paste, and powder. The container must be 3.4 ounces (100 milliliters) or smaller. Toothpaste tablets and tooth powder are alternatives that don’t need to be in the quart bag.
Do you still have to put toiletries in a clear bag in 2026?
Yes, the clear bag requirement is still in effect in 2026. All liquids, gels, creams, and pastes must fit in a single quart-sized, clear, resealable plastic bag. This rule applies to all U.S. airports and has not changed despite the introduction of new CT scanner technology at many checkpoints.
Does mascara go in the 3-1-1 bag?
Yes, mascara is considered a liquid by TSA because of its wet formula. It must be in a container of 3.4 ounces (100 ml) or smaller and placed inside your quart-sized clear bag. The same rule applies to liquid foundation, lip gloss, and other wet makeup products.
How many 3 oz bottles can I bring on a plane?
You can bring as many 3-ounce bottles as fit inside your single quart-sized clear bag. In practice, most travelers fit 6 to 10 bottles comfortably. The bag must seal completely flat. If you need more than that, consider solid alternatives or pack extras in checked baggage.
Does makeup need to be in a ziploc bag for TSA?
Liquid and wet makeup products like foundation, mascara, lip gloss, and cream blush must be in the quart-sized clear zip-top bag. Powder makeup, pressed eyeshadow, lipstick sticks, and solid bronzer do not need to be in the bag. When in doubt, treat a makeup product as a liquid if it has a wet or creamy consistency.
Can I bring a 4 oz bottle on a plane if it is not full?
No, TSA measures container size by the printed volume on the label, not by how much liquid is inside. A 4-ounce bottle that is half empty still violates the 3-1-1 rule and will be confiscated at the security checkpoint. Only containers labeled 3.4 ounces (100 ml) or smaller are allowed, regardless of fill level.
Does the 3-1-1 rule apply to TSA PreCheck?
Yes, the 3-1-1 rule applies to all passengers, including those with TSA PreCheck. While PreCheck allows you to keep shoes, belts, and light jackets on, you still need to follow the liquids rule. The quart-sized bag requirement is enforced at PreCheck lanes the same as standard lanes.
Final Thoughts on Packing to Pass TSA’s 3-1-1 Rule
Packing a carry-on that passes TSA’s 3-1-1 liquids rule comes down to three things: container size, the quart bag, and consistency. Once you know the rules, packing takes five minutes and you stop worrying about getting items confiscated at the checkpoint.
Stick to containers of 3.4 ounces (100 ml) or smaller, pack them in one clear, resealable, quart-sized bag, and remove that bag at the security checkpoint. For longer trips, switch to solid toiletries to free up space. Follow these simple steps and you’ll never lose another item to TSA again.
Last updated: September 2026