What the 3-1-1 liquids rule means for cabin bags in 2026, how it relates to the 100 ml standard, and how to pack without tray drama.
What is the 3-1-1 liquids rule?
The 3-1-1 liquids rule is the US TSA cabin standard: containers of 3.4 ounces (100 ml) or less, in one quart-sized clear bag, one bag per passenger. Many countries use a similar 100 ml rule with a single clear bag. Treat 100 ml as your default even when some airports trial larger cabin allowances.
The nickname compresses three limits: container size, bag size, and bag count. Gels, pastes, creams, aerosols and many mascara-style products count as liquids for screening. your departure airport’s security page the week you fly — CT scanners can change local practice without changing your return airport’s rules.
Pack the cabin system with carry-on packing list and size the bag against airline limits in the carry-on checker. Personal-item quirks sit in airline personal item rules 2026.
If you prefer fewer bottles, build a short kit with best travel beauty products 2026 and generate a checklist via the packing list generator.
How do you apply 3-1-1 at the tray?
Decant into containers at or under 100 ml, place them in one transparent resealable bag, and present that bag separately when asked. Larger toiletries belong in checked baggage. Duty-free liquids in secure tamper-evident bags are a separate pathway with receipt rules.
Officers screen volume markings and bag clarity as much as brand names. A 120 ml bottle that is half full still fails if the printed capacity exceeds the limit. Labelled travel bottles save arguments. whether your airport still requires liquids out of the cabin bag or allows them to stay inside under new scanners.
Medically necessary liquids and baby food often have exemptions with inspection. Declare them early rather than hiding them under jumpers. Keep prescriptions readable.
One clear bag means one. Stuffing a second “just for skincare” bag is a common reason trays bounce. If your routine needs more volume, move bulk products to the hold or buy miniatures after security.
| Item type | Cabin approach | Usually better in hold | Note |
|---|---|---|---|
| Shampoo / conditioner | 100 ml bottles in clear bag | Full-size bottles | Solids and bars skip the bag |
| Sunscreen | Travel SPF under 100 ml | Beach bottle for the trip | Creams count as liquids |
| Toothpaste | Travel tube in clear bag | Family-size tube | Pastes count |
| Perfume | Mini atomiser | Larger bottle if allowed in hold | Aerosols have airline limits |
| Duty-free spirits | STEBs + receipt when required | n/a for cabin purchase | Connecting security may re-screen |
Is 3-1-1 the same as the UK 100 ml rule?
Functionally yes for planning: UK and many European airports still centre on 100 ml containers in a single transparent bag, even though branding differs from TSA’s 3-1-1 slogan. Some terminals with advanced scanners have published larger cabin liquid allowances — your destination or connection may not.
Never plan a trip around the most generous airport on the itinerary. Pack for the strictest screening you will face that day. both departure and transfer airport pages.
Bag size still matters when liquids compete for under-seat space. See underseat vs overhead bag guide if you fly with a personal item only.
Airport parking, lounge time and bag storage around tight connections are logistics, not liquids rules — Holiday Extras and Radical Storage-type services help when you need to shed bulk before a city day, not at the X-ray belt.
How can you reduce liquids stress without over-packing?
Prefer solid toiletries, share travel bottles across a household, and buy full sizes at the destination when stays are long. Keep the clear bag pre-packed at home so the night before departure is not a decanting emergency.
Minimalist packing reduces bottle count naturally — minimalist packing one-bag guide pairs well with a strict liquids bag.
Re-check rules after long gaps between trips. July 2026 guidance ages when airports expand CT lanes. A two-minute airport-page check beats a confiscated moisturiser.
- Does mascara count? — Usually yes; treat cosmetics that are creamy or gel-like as liquids.
- Can I take a full water bottle? — Empty through security, then refill airside.
- What about contact lens solution? — Often allowed with declaration when medically needed; still check volume rules.
- Is the quart bag exact? — Use a transparent resealable bag about one litre / one quart; opaque makeup bags fail.