The Edit — Travel
What You Can Actually Take Through Security
The liquid rule limits the container, not the contents: a half-empty 6-ounce bottle fails even though it holds under 3.4. Battery limits work in watt-hours, which is not what most power banks print.
This guide is research-led: we have not handled these units ourselves. If you buy through our links we may earn a commission — it never changes a pick. How we choose
The liquid rule is misunderstood in one specific way that costs people their toiletries. It limits the size of the container, not the amount of liquid inside it.
The quick list
Every pick, in order. Jump to the full test on any of them.
- Most-reviewed
18-Pack Travel Bottles for Toiletries, Silicone
12,490 ratings makes this the most-evidenced set here, and the container marking is what security reads rather than the contents.
4.5from 12,490 verified reviews 16-Pack Leakproof Squeezable Travel Bottles
2,192 ratings, and leakproof is the specification that matters second, because pressure changes push liquid out of a badly sealed cap.
4.5from 2,192 verified reviewsCosywell 13-Piece 2 oz Travel Bottles Kit
2 ounce bottles, comfortably inside the limit, which removes any argument about whether a marking is legible.
4.5from 616 verified reviewsTravel Bottles for Toiletries, 3 oz Containers
9,999 ratings on 3 ounce bottles, which sit just inside the 3.4 ounce limit with no room for a worn label.
4.4from 9,999 verified reviews
3-1-1 is a container rule
Each container must be 3.4 ounces, or 100 millilitres, or smaller. They all go in 1 clear quart-sized resealable bag, and each passenger gets 1 bag.
A 6-ounce bottle with an inch of shampoo left in it does not pass. The officer is reading the capacity moulded or printed on the bottle, and a bottle that says 6 ounces is a 6-ounce container however empty it looks.
That is why decanting works and rationing does not. Buy bottles marked at or under the limit and keep the marking legible, because a rubbed-off label turns a compliant bottle into an argument.
| Counts as a liquid | Notes |
|---|---|
| Gels, pastes, creams | Toothpaste and deodorant sticks vary |
| Aerosols | Including dry shampoo |
| Mascara and liquid foundation | Yes, surprisingly often forgotten |
| Peanut butter, yoghurt, soft cheese | Spreadable means liquid |
| Solid soap, bar shampoo, powder | Not liquids, no limit |
Medications and infant formula are handled separately and in reasonable quantities, declared at the checkpoint rather than in the bag.
Travel Bottles for Toiletries, 3 oz Containers
9,999 ratings on 3 ounce bottles, which sit just inside the 3.4 ounce limit with no room for a worn label.
Current price shown on Amazon. We may earn a commission.
| Capacity | 3 oz each |
|---|---|
| Evidence | 9,999 ratings |
| Watch | Keep the marking legible |
9,999 ratings on 3 ounce bottles, which is the largest practical size inside the limit and leaves 0.4 ounces of margin.
The catch is the marking. On a squeezable bottle handled wet, printed capacity wears off, and a bottle with no legible size is one an officer has no reason to accept. Check it before each trip.
Buy it if
- You want maximum volume inside the rule
- A deep evidence base matters to you
Don't buy it if
- The printed capacity rubs off easily
Batteries are measured in watt-hours
Lithium battery limits are expressed in watt-hours, not milliamp-hours. Under 100 watt-hours travels freely in the cabin, and 100 to 160 watt-hours usually needs airline approval.
Most power banks print milliamp-hours, which is not the same unit. The conversion is simple: multiply milliamp-hours by the voltage, then divide by 1,000.
A typical bank runs at 3.7 volts. So a 20,000 mAh bank is about 74 watt-hours and travels without fuss, while a 27,000 mAh bank is around 100 and is at the threshold.
Good manufacturers print the watt-hour figure on the casing. Where it is absent, do the arithmetic before you pack rather than at the gate. How many phone charges each size actually delivers is worked through in portable charger mAh, explained, and one of the best-selling 10,000 mAh units has its own evidence profile.
| Power bank | Roughly | Status |
|---|---|---|
| 10,000 mAh | 37 Wh | Cabin, no issue |
| 20,000 mAh | 74 Wh | Cabin, no issue |
| 27,000 mAh | 100 Wh | At the threshold |
| Above that | Over 100 Wh | Airline approval |
Spare batteries never go in the hold
Any loose lithium cell travels in the cabin. That includes power banks, spare camera batteries, and the batteries in a device you are not carrying with you.
The reason is fire response. A cell in thermal runaway reaches several hundred degrees in seconds, and in the cabin that is noticed and dealt with where in a cargo hold it is not.
Tape the terminals or keep each cell in its own pouch so nothing can short against keys or coins. Devices with batteries installed may be checked, though the advice is increasingly to keep those with you as well.
Several carriers have tightened this further, with rules about using or charging power banks in flight. Check the airline rather than assuming.
18-Pack Travel Bottles for Toiletries, Silicone
12,490 ratings makes this the most-evidenced set here, and the container marking is what security reads rather than the contents.
Current price shown on Amazon. We may earn a commission.
| Count | 18 pieces |
|---|---|
| Material | Silicone, squeezable |
| Check | Stated capacity on the bottle |
12,490 ratings makes this the most-evidenced travel bottle set on the shelf, and silicone squeezes down as it empties, which stops the last third being unusable.
Eighteen pieces is more than most trips need. The useful part of a large set is having spares when a seal fails rather than filling all 18.
Buy it if
- You want the deepest evidence base available
- A full set for a long trip
Don't buy it if
- You need only 3 bottles
The things that surprise people
Powders over about 12 ounces may need separate screening on some routes, which catches protein powder and loose tea.
Ice packs and gel packs must be frozen solid at the checkpoint. Partially melted is a liquid.
Duty-free liquids bought after security are fine until you transfer through another checkpoint, where an unopened tamper-evident bag with the receipt inside is what keeps them.
Empty bottles pass fine and can be filled after security, which is the cheapest way to carry more than the rule allows.
Cosywell 13-Piece 2 oz Travel Bottles Kit
2 ounce bottles, comfortably inside the limit, which removes any argument about whether a marking is legible.
Current price shown on Amazon. We may earn a commission.
| Capacity | 2 oz each |
|---|---|
| Count | 13 pieces |
| Margin | Well under the limit |
Two ounce bottles sit well inside the 3.4 ounce limit, which removes any possibility of an argument about a worn marking or a rounding difference.
616 ratings. For short trips the smaller size costs nothing in practice, and the margin is worth more than the extra ounce on a route where enforcement is strict.
Buy it if
- You want no ambiguity at the checkpoint
- Short trips where 2 oz is plenty
Don't buy it if
- You need a fortnight of one product
16-Pack Leakproof Squeezable Travel Bottles
2,192 ratings, and leakproof is the specification that matters second, because pressure changes push liquid out of a badly sealed cap.
Current price shown on Amazon. We may earn a commission.
| Count | 16 pieces |
|---|---|
| Sold on | Leakproof seal |
| Suits | Cabin bags |
2,192 ratings, and leakproof is the property that matters once the compliance question is settled.
Cabin pressure falls during a climb, so air inside a partly filled bottle expands and pushes liquid past a weak seal. That is why bottles leak in flight and not in a bathroom cupboard.
Buy it if
- You have had a shampoo leak before
- You want squeezable rather than rigid
Don't buy it if
- You prefer glass or rigid bottles
Before you pack
Decant into bottles marked at or under 3.4 ounces, check the markings are readable, and put the bag where you can reach it without unpacking.
Then work out the watt-hours of every battery and move all of them into the cabin bag. Rules differ between authorities and change, so the operating airline is the final word. What the bag itself has to measure is in carry-on rules, and how to fit more into it is in what compression packing costs you.