Yes, a 3.38-fl-oz (100 ml) container is allowed in carry-on under the 3-1-1 rule, as long as it fits in your single quart-size liquids bag.
What 3.38 Fl Oz Means At Security
Three point three eight fluid ounces equals about one hundred milliliters, so the number on the bottle lines up with the common airport limit. Screeners read the label, not the fill line, so the container size is what counts. A travel bottle marked 3.38 fl oz or 100 ml fits the limit for a single item.
The rule in the United States is the familiar 3-1-1 setup: containers up to 3.4 ounces or 100 milliliters, all inside one clear, quart-size bag, one bag per passenger. You can read the official wording on the TSA liquids page. Bottles larger than the limit belong in checked baggage unless they meet a sealed duty free exception.
Outside the U.S., most airports still use the 100 ml rule as well. Some places are rolling out scanners that allow bigger amounts, but policies differ by airport. The safe approach is to pack like the limit still applies.
| Item | Carry-On | Checked Bag |
|---|---|---|
| Toiletries (shampoo, lotion, toothpaste) | Up to 3.4 oz / 100 ml each, all in one quart bag | No standard volume cap |
| Drinks brought from home | Not allowed above 3.4 oz / 100 ml | Allowed if sealed well |
| Duty free liquids in security-sealed bag | Allowed when sealed with receipt and screening clears | Allowed |
| Medically needed liquids, baby food, breast milk | Allowed in larger amounts with screening | Allowed |
| Alcohol (packed by you) | Mini bottles must fit the quart bag; open containers not allowed | Spirits between 24% and 70% ABV are limited; over 70% banned |
Bringing 3.38 Fl Oz On A Plane: The Label Rule
The printed capacity on the container is what officers go by. A half-full eight-ounce bottle still fails, while a 3.38-fl-oz bottle filled to the brim passes. If the package only shows milliliters, look for 100 ml or less. If it only shows ounces, a mark of 3.4 oz or less works.
Container Size Vs Filled Amount
Think of the container as the ticket. If the ticket says 3.38 fl oz or 100 ml, it can enter the baggie. If the ticket says more, it cannot, even when it holds less at the moment. That’s why refillable bottles labeled for travel are handy.
The Quart-Size Bag Explained
Each traveler gets one transparent, resealable bag that holds roughly one liter. All your travel-size liquids need to fit inside and the seal has to close. If the bag bulges and won’t close flat, expect a repack at the checkpoint. A fresh, sturdy bag saves time.
Where 3.38 Fl Oz Works Worldwide
In the U.S., a 3.38-fl-oz bottle sits under the limit. The same size is accepted across most of Europe and many other regions because the cap is set at 100 ml. The naming differs, yet the line in the sand is the same.
U.S. Airports
Security follows the 3-1-1 rule. That means travel-size containers up to 3.4 oz or 100 ml inside one quart bag. A 3.38-fl-oz label equals 100 ml, so it fits. Duty free liquids larger than that can pass screening only when sealed in an approved tamper-evident bag and the inspection clears.
EU And UK Airports
Most airports still cap carry-on liquids at 100 ml per container and expect a one-liter bag. The United Kingdom notes that some airports may allow up to two liters under new scanners, yet many still enforce 100 ml. The government’s guidance spells this out on its liquids page. When routes connect through different airports, stick to 100 ml to avoid trouble on the next leg.
Edge Cases People Ask About
Toiletry Sets And Multi-Packs
Each bottle in a kit has to meet the size limit on its own, and every piece still goes in your quart bag. A boxed set that wraps several bottles together can trigger extra screening. Slip each piece into the bag and keep the box in your carry-on or check it.
Refillable Bottles And Squeezies
Empty travel bottles are fine in any size, but once filled they need to show a marked capacity of 3.4 oz or 100 ml or less. If a refillable has no marking, fill it modestly and keep it in the bag with your other liquids. Clear bottles help screeners see the contents quickly.
Aerosols And Sprays
Hair spray, deodorant, shaving gel, and similar items count as liquids. Use travel sizes that meet the 3.4-oz limit and place them in the bag. Large spray cans belong in checked luggage, and any can with flammable gas should stay within airline limits.
Makeup And Toiletry Oddballs
Liquid lipstick, nail polish, liquid foundation, and small jars of cream all count. Solid deodorant sticks, bar soap, solid shampoo bars, and powder makeup are not part of your liquid allowance and can ride outside the bag. When in doubt, treat it like a liquid to avoid a repack.
Medically Needed Liquids And Baby Items
There is a standing exemption for prescription liquid medicine, baby formula, breast milk, and toddler drinks. Bring only what you need for the trip, declare it to the officer, and expect extra screening. You do not have to squeeze these into the quart bag, yet keeping them together speeds things up.
Checked Bag Rules For Liquids
Regular liquids can go in checked bags with few volume limits. Seal caps well and use leak-proof bags. Alcohol has special rules: beer and wine are fine; spirits between twenty-four and seventy percent ABV are capped in quantity per traveler; anything stronger is banned. Pack retail-sealed bottles upright and cushion them.
Aerosol rules also differ in the hold. Personal care sprays often have set weight caps per person. Big paint or solvent cans are usually prohibited. If an item could burn, explode, or leak fumes, assume a ban and check airline pages.
Simple Math: Ounces To Milliliters
The U.S. ounce equals 29.5735 milliliters. That makes 3.4 oz about 100.55 ml, while 3.38 oz comes out close to 100 ml. Here’s a quick chart you can use when labels switch units.
| Label (US fl oz) | Milliliters | Carry-On OK? |
|---|---|---|
| 1.0 | 29.6 ml | Yes |
| 1.7 | 50 ml | Yes |
| 2.0 | 59 ml | Yes |
| 2.5 | 74 ml | Yes |
| 3.0 | 88.7 ml | Yes |
| 3.38 | 100 ml | Yes |
| 3.4 | 100.6 ml | Yes |
| 4.0 | 118 ml | No for carry-on |
Travel brands often print both measures on packaging. If your favorite bottle lists only milliliters, look for one hundred or less for carry-on. Anything bigger rides in the checked bag or stays home.
Packing Tips That Save Time
Pre-Sort Liquids At Home
Load your quart bag before you leave. Put daily items near the top so you can grab them at a sink later. Group spill risks like oils into a small zip bag inside the quart bag to protect the rest of your kit.
Use Solid Alternatives When You Can
Swap liquid soap, shampoo, and conditioner for bars or powders on short trips. That clears space in your quart bag for sunscreen or contact solution. It also cuts leaks.
Keep The Bag Handy At The Line
Place the quart bag in an outer pocket. Many checkpoints ask you to remove it for a tray. Even at lanes that keep bags inside, easy access helps if an officer needs a closer look.
Pick Leak-Safe Caps
Flip-tops can pop under pressure. Screw-tops with inner seals hold better. A strip of tape over the cap adds peace of mind on long flights.
Mini Checklist Before You Leave
- Each liquid container reads 3.4 oz / 100 ml or less.
- All travel-size liquids fit in one resealable quart bag that closes flat.
- Medically needed liquids and baby items are set aside for separate screening.
- Anything larger lives in checked luggage or stays home.
- For connections through different airports, stick to the 100 ml plan.
- Duty free liquids stay sealed in their security bag with the receipt.
- Alcohol in checked bags stays below the strength and quantity caps.
Common Mistakes That Trigger Bag Checks
A few small slip-ups cause the most delays. The big one is tossing full-size bottles into a carry-on “just to see if it passes.” Screeners pull the bag, pull the bottle, and you lose both time and the item. Another repeat issue is mixing liquids into pockets and pouches across the bag, which forces a full search. Keep every liquid in the quart bag unless it is duty free, baby food, or medicine set aside for screening.
Personal Item Liquids Count Too
The 3-1-1 rule applies to both your main carry-on and your personal item. If you split liquids between bags, the total still needs to fit in one quart bag. Pack that one bag where you can reach it without digging.
Duty Free On Connections
Large perfumes or liquor bought after security can fly on your first leg when sealed in a tamper-evident bag with the receipt. Trouble starts when a connection forces you through security again and the seal breaks. Keep the bag sealed until your trip ends. If you must open it, move the bottle to checked baggage before the next checkpoint.
That’s it. With a simple plan and a clear quart bag, a 3.38-fl-oz bottle glides through carry-on screening at nearly any airport. Pack light, seal tight, and roll on to the gate. Checkpoints vary by lane and airport, so a tidy bag and clear labels speed the line. Smart packing keeps you within the rules and out of secondary screening.