Last Updated on February 20, 2022
The TSA liquids rule limits us to taking bottles or containers that are 3.4 oz.
This is because 3.4 oz is equivalent to 100 ml and it brings the TSA into line with the rest of the world who are using milliliters and the metric system.
But what if your bottle is 4 oz? It’s only 0.6 oz more, will the TSA let a 4 oz bottle pass the security checkpoint?
What if the bottle isn’t even full and has less than 3 oz of liquid inside? Is a 4 oz container travel size?
Let’s find out.
Can You Take 4 Oz On The Plane?
Simply put, no!
The TSA is very strict about this. If your bottle or container says 4 oz on the label they won’t let it through.
Often times if a small almost travel-size bottle was in your quart-size toiletries plastic bag the TSA might not realize it is slightly too big.
But if they do realize they will make you either check your bag or surrender the product i.e. throw it in the trash can.
You can’t even take 3.5 oz liquids on a plane. The rules are the rules.
But are there any exceptions that allow 4 oz bottles on the plane?
Let’s have look at @AskTSA on Twitter to see.
Jeff was able to bring a 4 oz bottle of water that he was using to make baby formula:
Lori was able to bring a 4 oz bottle of cough medicine:
The 3.4 oz liquids rule does not apply to bringing medicine on a plane whether it’s prescription medicine or over-the-counter.
Malynda tries to bring a 4 oz yogurt on her flight but the TSA says it’s not allowed:
Tabitha discovered that she could take her 4 oz bottle of contact lens solution.
The Verdict
For most types of liquid, your 4 oz bottle just isn’t going to happen. The security officers will not allow 4 oz bottles through security screening.
The exceptions are for medicine or medically necessary liquids.
You can also bring breast milk, formula, or juice for infants.
If you’ve purchased your liquids after the security checkpoint you can bring larger bottles.
If your liquid container is too large the simple thing to do is to transfer some into a smaller bottle. Travel-size silicone bottles are a great thing to have because of this.
They will save you money in the long run because travel-size versions of products are so damn expensive at the drugstore.