Airplane Liquid Limits: TSA 3-1-1 and 100 ml Rules

TSA’s travel checklist writes the rule as three lines: 3.4 ounces or less per container, one quart-size clear zip-top bag, one bag per passenger. The “3” is 3.4 ounces, not 3 ounces. A 3-ounce bottle clears. A 4-ounce bottle fails, even if it is half empty, because the limit is the container, not the remaining product.

The bag is a screening tool, not a toiletry system. TSA does not print a ruler. The common US freezer-bag face is 7 x 8 inches, and the volume is 1 quart (0.95 L). That measurement lives on our page for quart-size bag dimensions. If the bag will not close, or if it is opaque, expect to restow at the belt.

The rule is a carry-on checkpoint rule. Checked bags do not use 3-1-1. They still have FAA limits on aerosols and alcohol, covered below.

TSA’s liquids page says travel-sized containers that are 3.4 ounces or 100 milliliters or less per item. Manchester Airport says the same thing in plainer English: a container larger than 100 ml cannot go through even if it is only part full. Pack by the number printed on the bottle.

If a favorite full-size bottle has to fly, it goes in the hold, or it gets poured into a 3.4 oz bottle before you leave. The refillable bottles that actually hold a seal are the ones we listed with travel-size bottles.

TSA groups liquids, aerosols, gels, creams, and pastes together. The FAQ names toothpaste, shampoo, conditioner, mouthwash, and lotion. Toothpaste is on its own What Can I Bring page at 3.4 oz. Sunscreen is the same, including spray.

Canada’s CATSA list is useful because it names the items people argue about. Gels include peanut butter, jam, yogurt, pudding, chocolate spread, and cheese spread. Liquid cosmetics include mascara, liquid foundation, and liquid eyeliner. Aerosols include hairspray, body spray, shaving cream, and aerosol deodorant. TSA’s peanut butter row matches the 3.4 oz cap.

Solid stick deodorant is not in that group. TSA’s solid deodorant page says yes in carry-on and checked, with no 3.4 oz line. Heathrow’s liquids FAQ puts solid lipstick and stick deodorant outside the liquid list, and roll-on deodorant inside it. If it can be poured, sprayed, spread, or squeezed at room temperature, pack it as a liquid.

Water over 3.4 oz does not go through a TSA checkpoint. CATSA tells you to drink or discard it before the line and refill after. Heathrow lets 2-litre containers through, and still asks you to empty reusable metal or insulated bottles before screening.

The 100 ml cap is still the default on most of the trip. A handful of UK airports with CT scanners print 2 litres for their own departures. That is a departure-airport rule. It is not a cabin rule for the rest of the itinerary.

Heathrow adds two destination overlays on the same page. Liquids in containers over 100 ml cannot go on flights to Australia. Powders over 350 g or 350 ml are not allowed in the cabin on flights to the United States, with listed exceptions for medicines, baby powder, and human ashes.

Pack to 100 ml unless the departure airport’s own page currently says otherwise. Do not trust a third-party “scrapped the 100 ml rule” list. Manchester’s scanners are in, and the 100 ml cap is still in force while it waits on the Civil Aviation Authority.

Medically necessary liquids, medications, and creams can exceed 3.4 oz in a TSA carry-on. Take them out of the bag and declare them. TSA recommends a clear label. CATSA allows prescription medicines and essential non-prescription liquids (contact solution, cough syrup, eye drops, decongestant spray) over 100 ml, presented separately. Documentation is not required at either checkpoint. A pharmacy label still speeds the conversation up.

Formula, breast milk, juice, toddler drinks, and baby/toddler food, including puree pouches, can exceed 3.4 oz in a TSA carry-on and do not need to fit in the quart bag. You do not need to travel with the child to bring breast milk. Ice packs and freezer packs for those items are allowed; if they are slushy, they get the same extra screening. CATSA limits baby food and drink over 100 ml to travel with an infant younger than two, and still allows breast milk with or without the child.

Duty-free liquids over 3.4 oz can ride in a US carry-on on an inbound international itinerary if three things are true: the purchase was international, the bottle is in a transparent tamper-evident bag with no signs of tampering, and the original receipt is in the bag for a purchase made within 48 hours. TSA still recommends putting oversized liquids in checked baggage, even in that bag. If the item alarms or cannot be screened, it will not stay in the cabin.

3-1-1 does not apply to checked bags. Full-size shampoo and sunscreen belong there. Tighten the cap, keep the bottle upright when you can, and put it in a leak-proof pouch.

Aerosols still have an FAA cap in checked baggage. TSA’s sunscreen page restates it: toiletry and medicinal aerosols cannot exceed 0.5 kg (18 oz) or 500 ml (17 fl oz) per container, and the total per person cannot exceed 2 kg (70 oz) or 2 L (68 fl oz). Caps have to stay on so the nozzle cannot discharge. CATSA uses the same 500 ml per can and 2 L / 2 kg total for toiletry aerosols in checked bags, plus a one-canister limit on insect repellent.

Alcohol is a separate FAA rule. Mini bottles in a carry-on have to fit in the quart bag. In checked bags, drinks at 24% alcohol or less have no quantity cap from TSA. Drinks over 24% and not over 70% (140 proof) are limited to 5 litres (1.3 gallons) per passenger, in unopened retail packaging. Anything over 70% stays off the aircraft. You cannot drink your own alcohol on board unless a flight attendant serves it.

Put the liquids you will actually use in 3.4 oz bottles, drop them in one clear quart bag, and keep that bag where you can pull it in one motion. Dry items (solid deodorant, bar soap, toothbrush, razor, pills) can live in a separate pouch. That split keeps the quart bag closable and keeps toothpaste off a sweater.

A structured clear pouch survives more trips than a freezer bag. TSA does not certify toiletry bags, so “TSA approved” on a listing is seller language for “sized to the quart rule and clear enough to screen.” The kits we would actually pack are on our page for TSA toiletry bags.

At a US standard lane, the 3-1-1 bag comes out and goes in a bin. CATSA does the same except on CT-equipped lines, where the bag can stay inside the carry-on. Heathrow and Gatwick leave liquids in the cabin bag. If a later connection is a 100 ml checkpoint, pack to that checkpoint even if the first airport printed 2 litres.

The officer at the belt has the final say. TSA prints that on every What Can I Bring page. If an item alarms, it gets extra screening, and it can still be refused.