Can I bring toothpaste on a plane: the 3.4 ounce rule explained
Yes, you can bring toothpaste on a plane in your carry-on if the tube holds 3.4 ounces (100 ml) or less and sits in your quart-sized liquids bag. A bigger tube goes in checked baggage, where TSA lists toothpaste as allowed.
The limit follows the size printed on the container, not what is left inside. GOV.UK states that a container over 100 ml is refused even when it is only part full.
How the 3-1-1 rule treats toothpaste
TSA’s liquids rule covers liquids, aerosols, gels, creams and pastes, so toothpaste falls under it. You get one quart-sized bag, and each item inside must be 3.4 oz or 100 ml or less. Anything that alarms at screening gets additional screening, and the final call rests with the TSA officer.
Video: TSA
TSA’s own explainer above is short and worth a look if you rarely fly. Medications and infant or child nourishment are exempt from the limit, but ordinary toothpaste is not on that list.
Toothpaste tablets, powder and other formats
Tablets are solid, so the 3-1-1 rule does not apply to them in the way it applies to a tube. Powders are a separate case: TSA says powder-based substances over 350 ml (12 oz) in carry-on may need extra screening on flights into the US.
| Format | Carry-on status | Size limit | Source |
|---|---|---|---|
| Toothpaste tube or gel, 3.4 oz or smaller | Allowed, in the quart-sized liquids bag | 3.4 oz (100 ml) per container | TSA toothpaste page |
| Full-size tube over 3.4 oz | Not allowed in carry-on; allowed in checked bags | No stated limit in checked bags | TSA toothpaste page, TSA liquids rule |
| Large tube that is only part full | Still counts by container size | 100 ml container limit at most UK airports | GOV.UK hand luggage rules |
| Toothpaste tablets or powder | Not a liquid, gel or paste; powders over 350 ml (12 oz) may get extra screening on flights to the US | No 3.4 oz limit; 350 ml (12 oz) screening threshold for powders | TSA powders FAQ |
| UK airports with newer scanners | Some allow containers up to 2 litres | Check your departure airport | GOV.UK hand luggage rules |
Figures come from the TSA and GOV.UK pages named in the table. TSA’s toothpaste page was last updated in 2017, so check tsa.gov before a trip if the rule matters to you.
UK and other airports
At most UK airports you cannot take containers over 100 ml through security, and some airports now allow up to 2 litres. GOV.UK tells you to check the rules at every airport on your route, including the return leg.
You may also be asked to use a transparent resealable bag of up to one litre, roughly 20 cm by 20 cm. Not every airport requires it.
Packing toothpaste for a trip
A travel tube is enough for most trips. If you also pack for a child, remember that a rice-grain smear or a pea-sized amount is the usual guide, which is covered in how much toothpaste for kids.
Pick your formula before you leave. If you use an SLS free toothpaste, buy a travel size you can recognise instead of squeezing paste into an unlabelled pot, which is harder to recognise in a tray.
Mouthwash follows the same rule. A mouthwash spray counts as an aerosol or liquid, so it also needs to be 3.4 oz or smaller and live in the same quart bag.
This is general information about airline security rules, not dental advice.