You’re standing in the security line. The person in front of you is frantically digging through a backpack because they realized that expensive bottle of artisanal honey counts as a liquid. It's a mess. Most of us just want to know how many liquids can i bring in my carry on without getting pulled aside for a secondary screening that makes us miss our flight.
The short answer is the 3-1-1 rule. You probably know it, or at least you've heard of it. 3.4 ounces (100 milliliters) per container. One quart-sized bag. One bag per person. But honestly, it’s never that simple once you’re actually packing.
Does peanut butter count? Yes. What about that snow globe you bought for your niece? Definitely. The TSA defines "liquids" in a way that feels a bit aggressive—basically, if you can spill it, spray it, spread it, or pump it, it’s a liquid.
The Logic Behind the 3-1-1 Rule
We’ve been living with these restrictions since 2006. It started after a thwarted plot involving liquid explosives in the UK. Since then, the TSA (Transportation Security Administration) and international bodies like the EASA in Europe have strictly enforced volume limits.
The "3" refers to the 3.4-ounce limit. The first "1" is your single, clear, quart-sized plastic bag. The final "1" is you—one bag per traveler.
If you have a 6-ounce tube of toothpaste that is almost empty, it doesn't matter. The TSA looks at the size of the container, not the amount of product inside. If the tube says 6 ounces, it goes in the trash. It feels wasteful, I know. But the agents don't have the time to measure the volume of your leftover Crest.
What Actually Counts as a Liquid?
This is where people get tripped up. It’s not just water and shampoo. You have to consider "gels" and "aerosols" too.
Think about your morning routine. Shaving cream? Liquid. Hair gel? Liquid. Contact lens solution? Technically a liquid, but there's a loophole for that which we’ll get into later. Even things like hummus, jam, or salsa fall under the ban if they are over 3.4 ounces.
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I once saw a guy try to bring a large jar of coconut oil through. He argued it was a solid because it was cold and firm. The TSA agent didn't care. At room temperature, it melts. Into the bin it went.
The Total Count: How Much Can You Really Fit?
People often ask "how many liquids can i bring in my carry on" as a numerical question. Is it five bottles? Ten?
The truth is, there is no specific bottle count. Your limit is whatever fits comfortably inside that one-quart bag. If you are a master of Tetris and can fit 15 tiny bottles of essential oils in there, you are golden. If you have three bulky travel-sized sunscreens that fill the bag, then three is your limit.
The bag must be able to zip closed. If it’s bursting at the seams or held together with duct tape, an agent might make you toss some items.
The Medical and Baby Exceptions You Need to Know
There are "exempt" liquids. These don't have to fit in your quart-sized bag.
Medically necessary liquids, medications, and baby formula/breast milk are allowed in "reasonable quantities." This means you can bring a 12-ounce bottle of contact lens solution or a 10-ounce bag of breast milk. However, you must declare these to the officer at the start of the screening process.
Don't just leave them in your bag. Pull them out. Put them in a separate bin. They will likely be X-rayed, and sometimes they use a special scanner to test the vapor coming off the liquid. It adds two minutes to your wait, but you get to keep your stuff.
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International Variations and the 2026 Landscape
If you are flying within the UK or parts of Europe, things are changing—but slowly. Some airports, like London City or Teesside, have installed advanced CT scanners. These machines allow passengers to leave liquids in their bags and have even raised the limit to two liters in some cases.
But don't rely on that yet.
Most major hubs like Heathrow or JFK still require the old-school 3.4-ounce limit. If you’re flying from a high-tech airport to a smaller one, you might get through the first leg fine and then get stuck on your layover. Always pack for the strictest rule. Better safe than standing in a terminal in Frankfurt losing your favorite cologne.
How to Pack Like a Pro
Switch to solids where you can. It's the easiest "hack."
Bar soap instead of body wash. Solid perfume instead of spray. Toothpaste tabs instead of tubes. These don't count toward your liquid limit at all. You could have a suitcase full of bar soap and the TSA wouldn't blink.
Also, buy a high-quality, reusable TSA-approved bag. Those cheap Ziplocs rip. A sturdy, clear TPU bag with a zipper lasts for years and usually has a slightly more "forgiving" shape than a standard sandwich bag.
Duty-Free: The Trap
You bought a bottle of expensive Scotch in the Duty-Free shop in Dubai. You’re flying to New York with a connection in London.
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Be careful.
If you have a connecting flight and have to re-clear security, that Scotch is a liability. Unless it is packed in a Secure Tamper-Evident Bag (STEB) with the receipt visible and was purchased within the last 48 hours, the TSA might confiscate it during your transfer. If you’re flying direct, you’re fine. If you have a layover, keep that receipt and keep that bag sealed tight.
Final Summary of the Rules
When figuring out how many liquids can i bring in my carry on, keep these specific points in mind:
- The container size is the law. 3.4oz/100ml is the max, even if the bottle is half empty.
- The quart-sized bag is your boundary. If it doesn't fit, it doesn't fly.
- Declare your "extras." Meds and baby food are allowed but need a heads-up.
- Solids are your best friend. Swap what you can to avoid the liquid bag entirely.
The rules haven't fundamentally changed much in twenty years, but the enforcement can vary depending on the mood of the airport. Don't be the person arguing about the fluidity of peanut butter. Pack light, pack clear, and keep your "non-liquid" liquids (like meds) separate.
Before you head to the airport, do a final "squeeze test" on your quart bag. If it zips without a struggle, you’ve answered the question of how many liquids you can bring. You've brought exactly enough.
Next Steps for Your Trip:
- Check your labels: Look at the bottom of your "travel size" bottles; some are actually 4oz, which will get flagged.
- Inventory your "mushy" items: Move items like mascara, lip gloss, and concealer into the liquid bag, as these are often the "stealth" items that trigger a bag search.
- Separate your meds: Place any larger medical liquids in a small mesh pouch so you can pull them out instantly at the bin.