The Flight 100ml Liquids Rule Explained (2026)

Packing for a flight can be a stressful balancing act. Between weight limits, baggage fees, and security regulations, there is one rule that consistently trips up even the most seasoned travellers: the 100ml liquids rule.

We have all been there — standing in the security line, watching a beloved bottle of perfume, high-end face cream, or even a jar of peanut butter get swept into the bin. But why does this rule exist? What actually counts as a "liquid"? And how are new security technologies in 2026 changing the way we pack?

🛡️ 1. Why Does the 100ml Rule Exist?

The restriction on carry-on liquids has its roots in global security history. In August 2006, British police thwarted a major terrorist plot to detonate liquid explosives disguised as soft drinks aboard transatlantic flights.

In response, aviation authorities worldwide established a compromise based on extensive laboratory testing: the 100ml (3.4 ounces) limit. Scientists determined that liquid explosives in volumes under 100ml could not be easily combined to create a blast of critical mass. This compromise has remained the global aviation standard ever since.

🧴 2. What Actually Counts as a "Liquid"? (The LAGs Definition)

Most travellers know that water and shampoo are liquids. However, airport security operates under a broader classification: LAGs — Liquids, Aerosols, and Gels. If an item can be poured, squeezed, sprayed, smeared, or spread, it is a liquid.

Here are some of the most commonly confiscated items people get wrong:

• Spreads and Foods: Peanut butter, Nutella, hummus, honey, maple syrup, jam, cream cheese, and wet pet food are all classified as liquids. Even a soft creamy cheese like Brie can be confiscated if it exceeds 100ml.
• Cosmetics and Toiletries: Mascara, liquid foundation, lip gloss, toothpaste, creams, lotions, hair gel, and roll-on deodorants are all LAGs.
• Aerosols: Hairspray, spray deodorants, shaving cream, and dry shampoo fall under the liquids rule.
• Gelled items: Gel shoe inserts, gel-filled cooling packs, and snowglobes are also restricted.

The Golden Rule of Packing: If you can smear it, spray it, or squeeze it, treat it as a liquid. When in doubt, check your item on canitakethis.co before heading to the airport.

👜 3. The 3-1-1 / 1-Litre Bag Rule Explained

To bring liquids in your carry-on, follow these three rules (known as the 3-1-1 rule in the US):

• 100ml or Less: All liquid containers must have a maximum capacity of 100ml or less.
• 1 Clear Plastic Bag: All containers must fit inside a single, transparent, resealable plastic bag with a volume of no more than 1 litre (approximately 20cm × 20cm).
• 1 Bag Per Passenger: Each traveller is allowed only one liquids bag — it must be removed from your hand luggage and placed in a separate tray at the security scanner.

🛑 The "Container Capacity" Trap

The most common mistake travellers make is bringing a large bottle that is only partially full. Security measures the container's capacity, not the liquid inside. A 200ml bottle containing only 20ml of shampoo will be confiscated. Decant your liquids into travel-sized bottles (100ml or under) before your trip.

✨ 4. Crucial Exceptions to the Rule

🍼 Baby Milk, Formula, and Food

If you are travelling with an infant (typically aged 2 or under), you are permitted to bring breast milk, formula, sterilised water, baby juice, and baby food in quantities larger than 100ml. These items must be declared to security officers for separate screening but do not need to fit in your 1-litre bag.

💊 Prescription Medications and Medical Liquids

Essential liquid, gel, or aerosol medications are fully exempt from the 100ml rule — including insulin, saline solution, inhalers, and liquid cough medicines. Keep them in their original packaging with the pharmacy label, or carry a doctor's note explaining your medical necessity.

🛍️ Duty-Free Liquids

Liquids purchased at duty-free shops after the security checkpoint are exempt from carry-on limits, provided they are packed in a Secure Tamper-Evident Bag (STEB) by the store clerk. Do not open this bag until your final destination — if you have a connecting flight and must pass through security again, the bag must remain sealed with the receipt visible inside.

🚀 5. The 2026 Landscape: CT Scanners Changing the Rules

At some airports you may no longer need to remove liquids from your bags, thanks to the rollout of advanced CT / C3 security scanners that use 3D X-ray imaging to distinguish safe liquids from explosive chemicals.

However, the rollout is highly inconsistent. Many airports still operate older 2D scanners and strictly enforce the 1-litre bag rule. Even if your departure airport has upgraded scanners, your return airport or connecting hub might not. Always pack under the 100ml rule unless you are certain both ends of your trip support the new technology.

🔗 6. Checking Your Airline and Destination Rules

Individual airlines can enforce their own cabin constraints. Before you travel, verify your hand luggage size and weight limits — search our database of 78 airlines we cover or read a specific guide like the El Al Baggage Allowance Guide. Also use our customs search tool to confirm what is allowed past the border at your destination.

❓ 7. Frequently Asked Questions

Do wet wipes count as liquids?

No. Wet wipes, baby wipes, and makeup remover wipes are classified as solid items and do not need to go into your 1-litre liquids bag.

Does solid bar soap or solid deodorant count as a liquid?

No. Solid toiletries — bar soap, solid stick deodorant, solid perfume, and lipstick — are solids and are exempt from the liquids bag. Gel or roll-on deodorants, however, must go in the bag.

Can I bring contact lens solution?

Yes. Contact lens solution is classified as a medical liquid and is exempt from the 100ml limit, but you must declare it to security for separate screening. Many travellers prefer to pack travel-sized bottles (under 100ml) to save time at the scanner.

This guide was last updated in 2026. Because airline and customs security policies can shift, always verify your flight's exact baggage rules on canitakethis.co before you depart.