TSA's 3-1-1 rule is the US version of the 100ml/1-litre rule: 3.4oz (100ml) containers, in 1 quart-sized clear bag, 1 per passenger.
Last updated · Reviewed against current airport security guidance
TSA's 3-1-1 rule is the US version of the 100ml/1-litre rule: 3.4oz (100ml) containers, in 1 quart-sized clear bag, 1 per passenger.
Rule basis: General airport security guidance — rules can vary between airports and change over time. Confirm with your departure airport before you fly.
What to do: Pack to 100ml per container in a single 1-litre clear bag unless you've confirmed a larger allowance at both your departure airports.
Liquid Limits is a travel planning tool, not an official aviation source. Always confirm with the airport before you travel.
At a glance
Security · Airline · Border
Rules vary by airport — some still enforce 100ml, others now allow 2L containers in CT scanners.
Most airlines defer to airport security on liquids in the cabin.
Liquids themselves are rarely a customs issue — but contents (alcohol, dairy, CBD) might be.
Three separate rule systems · Any one can stop your item
3.4 ounces (100ml) per container · 1 quart-sized clear bag · 1 bag per passenger.
Medications, breast milk, infant formula and juice for infants are allowed in 'reasonable quantities' above the 3.4oz limit. Declare them at the checkpoint.
International arrivals are typically re-screened in the US, and duty-free STEBs over 3.4oz do not survive. Pack into checked bags before your US connection.