TSA's 3-1-1 liquids rule governs what size containers you can take in airplane carry-ons. This standard, unchanged as of March 2026, applies to U.S. flights and many international ones, stemming from post-2006 security measures to prevent liquid-based threats. Imagine packing your toiletries: each must fit snugly into a single clear bag, avoiding those heartbreaking confiscations at the gate.

Core Rule Breakdown

All liquids, gels, creams, pastes, and aerosols (like shampoo, lotion, toothpaste, or deodorant) follow these limits in carry-on bags:

  • 3.4 ounces (100 ml) maximum per container —check the label, as "travel-sized" often fits perfectly.
  • 1 clear, quart-sized (about 7x8 inches or 1 liter) zip-top bag per passenger—all items must fit inside with room to close fully.
  • 1 bag only —no extras, even for families; each traveler gets their own.

This "3-1-1" setup (3.4 oz, 1 quart bag, 1 person) streamlines screening: remove the bag from your carry-on and place it in a bin at security. For TSA PreCheck, you might skip removal, but always confirm locally.

What Counts as "Liquids"?

The rule covers more than water—think spreadable items like peanut butter or mascara. Solid foods and dry powders are usually fine, but creamy dips aren't.

  • Yes : Lip balm (if under 3.4 oz), contact solution (declare larger medical amounts).
  • No : Full-size sunscreen or perfume—pack in checked luggage instead.

Pro tip: Buy travel bottles (under $10 sets abound) to decant larger items; they're a game-changer for frequent flyers.

Item Type Carry-On Allowed? Notes
Shampoo (3 oz) Yes In quart bag
Lotion (4 oz) No Checked bag only
Duty-free liquor Yes, with conditions STEB-sealed, receipt, <48 hrs old
Baby formula Yes, reasonable amounts Declare at screening
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Exceptions and Special Cases

  • Medications and baby items : Larger volumes allowed if declared—screening officers may test them.
  • Duty-free purchases : Internationally bought liquids over 3.4 oz are okay in tamper-evident bags (STEB) with receipts, for U.S. connections.
  • International variations : Canada (CATSA) mirrors 100 ml max; EU uses similar "100 ml rule," but always check your origin/destination.

A traveler's tale: One forum user in 2025 breezed through with a sealed duty- free vodka, receipt in hand, while another's unchecked 4 oz serum vanished—lesson learned!

International vs. U.S. Flights

U.S. TSA sets the domestic tone, but airlines like Delta or United enforce it globally from U.S. hubs. Flying to Europe? Their 100 ml cap aligns closely, but post-Brexit UK tweaks (e.g., STEB for transit) add layers—double-check via airline apps. No major 2026 changes noted amid rising travel volumes.

Packing Tips for Smooth Sailing

  1. Prep ahead : Fill a see-through bag pre-flight; test closure.
  2. Checked bags win : Unlimited liquids there, but pack in sealed bags against leaks.
  3. Buy post-security : Airports stock compliant sizes.
  4. Stay updated : Rules hold steady, but follow @TSA on social for alerts.

TL;DR : Stick to 3.4 oz max per bottle in one quart bag per person—no recent changes.

Information gathered from public forums or data available on the internet and portrayed here.