What You Cannot Pack in a Carry-On
The prohibited list, the items that catch people out, and the reverse rule almost nobody knows — the things that must go in the cabin and never in the hold.
We have not tested this gear. Every figure here is compiled from published manufacturer specifications and published airline policies, and the arithmetic is public so you can check it. This page contains affiliate links — see the affiliate disclosure.
The main categories TSA prohibits in a carry-on are liquids over 3.4 oz outside the one-quart bag, most sharp objects, firearms and ammunition, flammable and pressurized items, self-defense sprays, and tools longer than 7 in. Several of these are allowed in checked baggage instead — and a few common items are the reverse, banned from the hold and permitted only in the cabin.
- Liquids, gels, aerosols and pastes over 3.4 oz / 100 ml per container
- Knives of any blade length, box cutters, razor blades that are not in a cartridge
- Scissors with blades longer than 4 in from the pivot
- Firearms, ammunition, replica firearms and gun parts
- Self-defense sprays, including pepper spray and mace
- Flammable liquids, aerosol paint, lighter fluid, camping fuel
- Tools longer than 7 in, and any drill, crowbar or hammer
- Sporting goods that could be used as a bludgeon — bats, clubs, cues
This page summarizes published TSA rules. TSA officers have the final decision on any individual item at the checkpoint, and the authoritative list is TSA’s own What Can I Bring? database. Check it for anything unusual.
| # | Product | Published material | Fits | Score | Price |
|---|---|---|---|---|---|
| 1 | Peak Design Small Wash Pouch (1L)Carry-on-only travel with a minimal routine | Weatherproof 200D nylon | 11 of 11AA DL UA WN … | 5.9 | $49.95 · Check on Amazon#ad How we earn |
| 2 | Anker PowerCore 10000 PD ReduxA phone-and-tablet power bank that never raises a question at a gate | 36.3 Wh lithium-ion, USB-C in/out plus USB-A | 11 of 11AA DL UA WN … | 5.8 | Check price on Amazon#ad How we earn |
| 3 | BAGSMART Blast 4.5L Hanging Toiletry BagCarry-on-only travel inside the TSA 3-1-1 limit | Water-resistant polyester | 11 of 11AA DL UA WN … | 5.7 | $17.99 · Check on Amazon#ad How we earn |
| 4 | BAGSMART Travel Electronics OrganizerCables and chargers only, at the lowest possible weight | Water-repellent polyester with elastic loops | 11 of 11AA DL UA WN … | 5.6 | $14.44 · Check on Amazon#ad How we earn |
| 5 | INIU B41 Slim 10000mAh Power BankBuyers who want the longest published warranty on a power bank | Approximately 37 Wh lithium-ion, USB-C in/out | Not published | 1.5 | $54.99 · Check on Amazon#ad How we earn |
Prices last verified October 19, 2026. Prices move — the figure you see on Amazon at the moment you click is the real one.
The liquids rule, stated precisely
The rule people call “3-1-1” is three separate constraints and most of the confusion comes from remembering only the first.
- 3.4 oz — the maximum size of any single container. Note that this is the container size, not the amount of liquid in it. A half-empty 8 oz bottle is prohibited.
- 1 quart — all those containers must fit in one clear, resealable quart-sized bag. A quart is 0.95 L, which is smaller than most people picture.
- 1 bag per passenger — you get one, and it comes out of the carry-on for screening.
“Liquid” is broader than it sounds: it includes gels, aerosols, creams, pastes and anything spreadable. Peanut butter, yoghurt, mascara, toothpaste and hummus are all liquids for this purpose. Solid deodorant, a bar of soap and a solid shampoo bar are not, which is why they are the standard workaround.
Exemptions exist for medically necessary liquids, breast milk, formula and baby food in reasonable quantities. Declare them at the checkpoint rather than hiding them in the quart bag — they are screened separately and they do not count against it. A toiletry bag with a separate clear pouch makes this materially faster.
The items that actually catch people
The prohibited list is mostly obvious. What costs people time and possessions is a much shorter list of items they assumed were fine.
| Item | Carry-on | Checked | The catch |
|---|---|---|---|
| Disposable and safety razors | Yes | Yes | The razor is fine. Loose blades and straight razors are not — the blade must stay in its cartridge. |
| Scissors | Under 4 in blade | Yes | Measured from the pivot, not overall length. Most nail scissors pass; most kitchen scissors do not. |
| Lighters | One, on your person | No | A common lighter is permitted in the cabin but prohibited in checked baggage. Torch lighters are banned outright. |
| Power banks and spare lithium batteries | Yes | No | Must travel in the cabin. This is a fire-safety rule, and it is enforced. |
| Snacks and solid food | Yes | Yes | Solid food is fine. Anything spreadable or pourable is a liquid and needs the quart bag. |
| Corkscrew with a foil cutter | No | Yes | The small blade makes it a sharp object. Bladeless waiter's friends are usually allowed. |
| Aerosol dry shampoo | Under 3.4 oz | Yes, limited | Aerosols are liquids for the quart bag, and checked aerosols are limited by volume too. |
| Knitting needles | Yes | Yes | Permitted, which surprises people. Circular thread cutters are not. |
The reverse rule: what must NOT be checked
This is the part of the rules that catches experienced travelers, because it runs the opposite way to everything else. A short list of items is prohibited in the hold and permitted only in the cabin, almost always for fire-safety reasons:
- Spare lithium batteries and power banks. Any loose lithium cell, including camera batteries and phone chargers with a battery in them, must be in the cabin where a fire can be seen and dealt with.
- E-cigarettes and vapes. Cabin only, and they must not be charged in flight.
- Lighters and matches. One common lighter or one book of safety matches on your person; neither in the hold.
- Anything with a large battery you cannot remove — some smart-luggage cases with non-removable batteries are prohibited as checked baggage entirely.
This matters more than it used to, because gate-checking a carry-on is now routine on full flights. If your bag can be taken from you at the door, the battery bank should not be inside it — keep it in your personal item, which stays with you.
A note on smart luggage
Suitcases with integrated batteries are permitted as carry-on where the battery can be removed, and are widely prohibited as checked baggage where it cannot. If you own one, know how the battery comes out before you are at a gate being asked to demonstrate it.
Outside the US
The 100 ml liquid limit is near-universal, but the details are not. Several major airports have installed CT scanners that permit liquids to stay in the bag and in some cases lift the volume limit entirely — and several have rolled that back again. The safe assumption when flying internationally is the strictest version of the rule: 100 ml containers in a one-liter bag, out of the case at the checkpoint.
Item-level rules differ too. Several countries prohibit items TSA permits, and a few permit items TSA does not. Check the departure airport’s own published rules for the outbound leg and the destination’s for the return — they are different authorities and they are not obliged to agree.
Every pick, with the working
Each entry below shows the published inputs, the four axis scores they produce, and what you give up. The order is the computed order, not a commercial one.
1 · Carry-on-only travel with a minimal routine
Peak Design Small Wash Pouch (1L)
1 L is almost exactly the quart the TSA allows, which makes this the only toiletry bag here sized to the actual legal constraint rather than to a shelf.
- Published size
- 10.2 × 5.1 × 3.9 in
- Weight
- 0.39 lb
- Capacity
- 1 L
- Weight per liter
- 0.39 lb/L
- Cost per covered year
- $2.50/yr
- Published list price
- $49.95
Warranty Peak Design lifetime product warranty
Fits 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY. See the limits.
What it does well
- 1 L published capacity is within 5% of the 0.95 L quart limit
- 6.2 oz, the lightest published weight in this category
- Same lifetime warranty as the larger pouch
What you give up
- $49.95 for 1 L is the highest cost per liter on this site
- Too small for a full skincare routine or a shared bag
- No clear pouch, so the liquids still come out loose at a checkpoint
The arithmetic behind the score
- Value 5.0/10 — $49.95 ÷ 20 yr = $2.50/yr; $49.95 ÷ 1 L = $49.95/L
- Airline-fit breadth 10.0/10 — Fits the published carry-on limit at 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY
- Carry efficiency 0.0/10 — 0.39 lb ÷ 1 L = 0.390 lb/L
- Warranty & support 8.0/10 — no stated end date (6 of 6); repair published (+2); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Peak Design published specifications and price, compiled 3 September 2026.
2 · A phone-and-tablet power bank that never raises a question at a gate
Anker PowerCore 10000 PD Redux
36.3 Wh is barely a third of the 100 Wh airline threshold, so it never needs approval — and at 6.8 oz it is the smallest thing on this site that will fully recharge a phone twice.
- Published size
- 4.17 × 2.05 × 0.98 in
- Weight
- 0.42 lb
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty 18 month limited warranty with lifetime technical support
Fits 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY. See the limits.
What it does well
- 36.3 Wh published, comfortably inside the 100 Wh limit airlines apply without approval
- 6.8 oz and 0.98 in thick — it disappears into a personal item
- USB-C carries both input and output, so one cable charges the bank and the phone
What you give up
- 18 months is the shortest published warranty of any product on this site
- 10,000 mAh is two phone charges, not a laptop
- No manufacturer-published price to compute cost per covered year
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 10.0/10 — Fits the published carry-on limit at 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 0.5/10 — 1.5 yr (0.5 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Anker published specifications, compiled 3 September 2026. Retail-channel pricing only. Check the live price before buying.
3 · Carry-on-only travel inside the TSA 3-1-1 limit
BAGSMART Blast 4.5L Hanging Toiletry Bag
4.5 L in a 10.6 oz bag that hangs — the smallest published toiletry volume here, which is the right size when the liquids rule caps you at a quart anyway.
- Published size
- 10.24 × 5.9 × 4.72 in
- Weight
- 0.66 lb
- Capacity
- 4.5 L
- Weight per liter
- 0.15 lb/L
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty No warranty term published
Fits 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY. See the limits.
What it does well
- 4.5 L published capacity is honest about how little liquid you can legally carry
- 10.6 oz published weight
- Hanging hook, which is the only thing that works in a hotel bathroom with no counter
What you give up
- No warranty term published
- 4.5 L is too small if you travel with a full skincare routine
- No separate quart bag included for the security tray
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 10.0/10 — Fits the published carry-on limit at 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY
- Carry efficiency 6.1/10 — 0.66 lb ÷ 4.5 L = 0.147 lb/L
- Warranty & support 0.0/10 — no published term (0 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: BAGSMART published specifications, compiled 3 September 2026. Retail-only pricing. Check the live price before buying.
4 · Cables and chargers only, at the lowest possible weight
BAGSMART Travel Electronics Organizer
0.24 lb and 1.4 in thick, which is a fifth of the Peak Design's weight — it slides flat against the back panel of a bag where the Peak Design has to be packed around.
- Published size
- 9.4 × 6.7 × 1.4 in
- Weight
- 0.24 lb
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty No warranty term published
Fits 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY. See the limits.
What it does well
- 0.24 lb published — the lightest organizer we have compiled
- 1.4 in deep, so it lies flat rather than occupying a corner
- Elastic loops in two sizes, which is the layout that keeps cables from tangling
What you give up
- No published warranty term at all
- No published capacity, so cost per liter cannot be computed
- Flat layout means nothing thicker than a small plug fits well
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 10.0/10 — Fits the published carry-on limit at 11 of 11 US carriers: AA, DL, UA, WN, AS, B6, F9, G4, HA, MX, SY
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 0.0/10 — no published term (0 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: BAGSMART published specifications, compiled 3 September 2026. Retail-channel pricing only. Check the live price before buying.
5 · Buyers who want the longest published warranty on a power bank
INIU B41 Slim 10000mAh Power Bank
Skip this one. Skip it on this page specifically. The rule that matters here is written in watt-hours, and INIU publishes no weight and no full dimensions to go with its capacity. If a gate agent asks you to demonstrate that a bank is under 100 Wh, you want the one with the figure printed on the case.
Twice the warranty of anything else in this category at roughly the same capacity — three years against Anker's eighteen months, on a product whose failure mode is the battery degrading.
- Published size
- Not published
- Weight
- Not published
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty 3 year INIU Care warranty with lifetime technical support
Fits No published dimensions to check.
What it does well
- 3 year published warranty is double Anker's on a comparable bank
- Roughly 37 Wh, well inside the 100 Wh threshold airlines apply without approval
- 0.5 in published thickness — one of the slimmest 10,000 mAh bodies sold
What you give up
- INIU publishes no full dimensions and no weight, so two of our axes cannot be scored
- 15 W output is slower than the fast-charging banks in the same size class
- No manufacturer-published price
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth not scored — No published dimensions to check against carrier limits.
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 1.5/10 — 3 yr (1.5 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: INIU published specifications, compiled 3 September 2026. INIU publishes a 0.5 in thickness and describes the body as slimmer than comparable 10,000 mAh banks, but no full three-dimensional figure we could read. Retail-channel pricing only. Check the live price before buying.
Prices last verified October 19, 2026. Prices move — the figure you see on Amazon at the moment you click is the real one.