You can usually fly with only small amounts of liquid in your hand luggage, but much more in checked bags, depending on country and airport rules.

Core rule: carry‑on liquids (the 3‑1‑1 rule)

For flights using TSA‑style security (e.g., the US, and many airports that mirror this standard):

  • Each liquid container in your carry‑on must be 3.4 ounces (100 milliliters) or less.
  • All your liquid containers must fit in a single, clear, resealable, quart‑size (≈1 liter) plastic bag.
  • You get one bag per passenger in your carry‑on.
  • Examples of what counts as a “liquid”: drinks, gels, creams, pastes, foams, sprays, many cosmetics, liquid foods like yogurt or soup.

A simple way to remember this is 3‑1‑1 : 3.4 oz bottles, 1 quart bag, 1 bag per person.

What this looks like in real life

Imagine you’re packing for a weekend trip with only a backpack:

  • 1 travel shampoo (100 ml)
  • 1 travel conditioner (100 ml)
  • 1 travel shower gel (100 ml)
  • 1 small toothpaste
  • 1 small sunscreen
  • 1 mini face cream

As long as each item is 100 ml or less and all of them fit and zip closed inside one quart‑size bag, you’re fine.

Common questions (quick answers)

“Can I bring a 4 oz bottle if it’s half full?”

No. The container size matters, not how much is inside. If the bottle is larger than 3.4 oz / 100 ml, it can be taken at security even if it’s only partly filled.

“Is there a limit to the number of small bottles?”

You can have as many 100 ml bottles as fit in your one quart‑size bag , and the bag must still be able to close. Typically that’s around 5–10 travel‑size bottles depending on shape.

“How much liquid can I put in checked luggage?”

  • Most ordinary liquids (like big shampoo bottles or drinks under 24% alcohol) are effectively unlimited in checked baggage, only restricted by your airline’s weight/size limits.
  • Alcohol 24%–70% ABV (spirits/liquor) is usually limited to 5 liters per passenger , in original unopened retail packaging.
  • Over 70% ABV (very high‑proof spirits) is not allowed in checked or carry‑on bags.

Special cases and exceptions

Certain items can exceed the 100 ml carry‑on limit, but they must be declared and screened separately:

  • Medically necessary liquids (e.g., prescription liquid meds, some medical solutions).
  • Baby formula, breast milk, and baby food needed for the flight.
  • Some liquid dietary or disability‑related items.

These don’t have to fit in your quart bag, but you should:

  • Take them out of your bag at security.
  • Tell the officer they’re medically necessary or for an infant.

Duty‑free liquids are another special case:

  • Duty‑free liquids bought after security , in a sealed, tamper‑evident bag , can be larger than 100 ml and carried on, including during US‑bound connections, as long as the bag is properly sealed and the receipt is visible.

International and “latest” twists

  • In most of the world , especially the US and many other regions, the 100 ml / 1‑liter bag rule is still the standard for liquids.
  • Some European airports have begun relaxing liquid rules where they’ve installed newer scanners, sometimes allowing larger amounts (up to around 2 liters per passenger), but this is not universal and can change.

Because rules can differ or change, especially in 2025–2026 as more airports upgrade scanners, it’s smart to:

  • Check your departure airport and airline guidance before you pack.
  • When in doubt, put large liquids in your checked bag or buy them after security.

Quick HTML table: key liquid rules

Here’s a compact HTML table summarizing the most important pieces:

html

<table>
  <thead>
    <tr>
      <th>Item</th>
      <th>Carry-on limit</th>
      <th>Checked bag limit</th>
      <th>Notes</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Regular liquids (toiletries, drinks)</td>
      <td>Max 3.4 oz (100 ml) per container; all must fit in 1 quart-size clear bag; 1 bag per person [web:1][web:3][web:9]</td>
      <td>Generally unlimited, subject to airline weight rules [web:1]</td>
      <td>Larger containers should go in checked baggage</td>
    </tr>
    <tr>
      <td>Duty-free liquids bought after security</td>
      <td>Can exceed 100 ml if in sealed, tamper-evident bag with receipt visible [web:1]</td>
      <td>Same as any liquid once checked in</td>
      <td>Keep bag sealed until final destination</td>
    </tr>
    <tr>
      <td>Medications & baby liquids</td>
      <td>Can exceed 100 ml if declared and screened separately [web:5][web:9]</td>
      <td>No special volume limit beyond standard safety rules</td>
      <td>Not required to fit in quart bag</td>
    </tr>
    <tr>
      <td>Alcohol & spirits (24%–70% ABV)</td>
      <td>Must follow 100 ml carry-on rule unless duty-free [web:1]</td>
      <td>Up to 5 liters per passenger in original packaging [web:1]</td>
      <td>Over 70% ABV banned in all baggage [web:1]</td>
    </tr>
    <tr>
      <td>High-proof alcohol (&gt;70% ABV)</td>
      <td>Not allowed [web:1]</td>
      <td>Not allowed [web:1]</td>
      <td>Considered too flammable</td>
    </tr>
  </tbody>
</table>

Mini story to make it stick

Picture this: you’re at security with a big 500 ml bottle of your favorite shampoo in your backpack. The officer pulls it out, shakes their head, and drops it into the bin. Ouch. If you had poured a bit into a 100 ml travel bottle for your carry‑on and put the big bottle in checked luggage, you would have kept both. That’s the everyday consequence of the 3‑1‑1 rule in action.

TL;DR: In your carry‑on, all liquids must be in containers of 3.4 oz / 100 ml or less , and all of them must fit in a single quart‑size clear bag (one per person). In checked baggage you can usually bring large bottles and multiple liquids, limited mainly by airline baggage rules and some extra limits for alcohol.

Information gathered from public forums or data available on the internet and portrayed here.