TSA Liquids: The 3-1-1 Rule Explained
Solid frozen liquids can skip the bag if fully frozen at screening.
Insulin, liquid meds, breast milk skip the size limit, just declare them.
Anything over 3.4 oz goes in checked luggage, not your carry-on.
You know the drill. Dig out the quart bag, dump the bottles on the belt, hope you packed it right. The 3-1-1 rule isn't actually complicated, TSA just never explains it anywhere useful. Here's the real breakdown, the exceptions that matter, and the stuff that gets your bag pulled for a second look.
What actually counts as a liquid
If it pours, spreads, sprays, or squishes, TSA counts it as a liquid. Doesn't matter if it's skincare or lunch.
The actual 3-1-1 breakdown
Three numbers, that's the whole rule. Everyone overcomplicates this.
100ml or less, per bottle. A half-empty 8 oz bottle still doesn't count.
Clear, resealable, roughly 7x8 inches. Not a gallon bag, not a Tupperware.
Pull it out and place it in a bin at screening unless your airport's scanner says otherwise.
What skips the 3-1-1 rule
A few categories get to ignore the size limit entirely. You just have to say something at the checkpoint.
Medically necessary liquids
Insulin, liquid medication, IV fluids
No limit
Baby formula and breast milk
Includes toddler drinks and purees
No limit
Duty-free liquids
Purchased past security
Sealed bag required
Mistakes that get your bag pulled aside
None of these are complicated, they're just easy to forget when you're rushing to your gate.
If it's bulging, it's getting flagged for a manual check. Pack fewer bottles, not a bigger bag.
The container size is what matters, not how full it is. A 5 oz bottle with an inch of shampoo left still gets tossed.
Gel eye masks, ice packs, gel insoles, all count. People forget these constantly.
Say it before the bin goes through the scanner, not after they find it.
Quart size only. Officers do actually check this.
The 3-1-1 rule is a regulated TSA policy, not a general guideline, so exact limits can vary slightly by exception category. Check tsa.gov before you fly if you're carrying anything unusual.