# Carry-on liquid limits: ~$15 TSA kit vs $30–$60 checked bag fees

Riley Quinn · November 1, 2026

> A $15 TSA-compliant liquids kit can beat $30–$60 each-way checked bag fees on US–Europe routes, as the best of seven tested bags costs just 18 cents.

| Takeaway | Detail |
| --- | --- |
| A roughly $15 TSA-compliant liquids kit costs less than one $59 checked bag on US–Europe routes. | Checked bag fees are $30–$60 each way; verify your carrier's current fee table. |
| The best of seven tested TSA-compliant liquids bags costs 18 cents. | The New York Times tested seven TSA-compliant liquids bags, and the best one costs 18 cents. |
| Carry-on-only packing is viable when you can live with 100ml containers. | The thesis applies to US–Europe round trips where 100ml containers are acceptable. |
| Book carry-on-only unless your itinerary forces at least two of three listed exceptions. | The listed exceptions are liquids over 100ml, a budget-carrier leg with no included cabin bag, and "a checked bag you were" as stated in the rule. |

 This guide compares a roughly $15 TSA-compliant liquids kit with checked-bag fees on US–Europe routes.

 It shows when carry-on-only packing with 100ml containers is the lower-cost choice.

## How the 3-1-1 Rule Actually Works

 Before packing for any US departure, the most important thing to know about TSA's 3-1-1 rule is that it is your container size, not the amount of liquid left inside, that gets you through security. According to TSA guidance, each container must be 100ml (3.4 oz) or less, all of those containers must fit in one quart-size clear bag, and only one such bag is allowed per passenger. A bottle that is larger than 100ml will not be accepted, even if it is nearly empty. This is the mechanic that determines whether your liquids pass the checkpoint, not how much product remains.

 With that said, clearing security in the United States is only one part of a US–Europe round trip. EU airports apply their own 100ml limit on onward connections, so a kit that clears a US checkpoint must also clear security at any EU airport where you will re-clear before a regional hop. The process may look similar, but the enforcement is handled by that airport's own security, and you cannot assume it will be identical to your outbound experience. For this reason, you should check your EU arrival airport's security rules separately for any connection where you know you will go through screening again.

 The safest method is to confirm current TSA liquids guidance at tsa.gov before any US departure, and to verify the rules for each EU airport where re-screening is planned. Don't rely on old screenshots or a trip from years prior, as the public guidance is the thing to check for your exact airports. This is a verification step, not a guess, and it only takes a moment to do.

 Ultimately, the quart-size bag is the container that the rule is built around. If every liquid item you need is in its own container of 100ml or less and all of those containers fit inside that single bag, you are working within the 3-1-1 structure. If even one of those containers is over 100ml, the container itself is the issue, regardless of brand or purpose. For the mechanics alone, that is the line between passing and being pulled for your liquids.

![How the 3-1-1 Rule Actually Works — Carry-on liquid limits](https://screenshots.mightytravels.com/article-images-ai/carry-on-liquid-limits-15-tsa-kit-vs-30-ai-efc20698.jpg)

## What Independent Testing Found

 For kit choice alone, the clearest evidence base comes from two independent media tests. *The New York Times* tested seven TSA-compliant liquids bags and found the best performer costs 18 cents — a standard quart zip-top bag beat purpose-built cases on compliance and speed at security. The direct check for any traveler is shape: if the bag can lie flat and only hold containers that fit the quart limit, it can satisfy the shape requirement without paying for extra features. Treat that 18-cent figure strictly as the result of that test, not a guaranteed price at every store.

 That said, compliance is only one job. *WIRED*, in its roundup *Carry All Your Little Soaps and Creams in the Best Tested Toiletry Bags*, independently tested toiletry bags for carrying soaps and creams. This confirms that a second category of hanging/dopp kits exists, but it is relevant only once you are past security and need organization, not compliance. The distinction matters: a bag can be excellent for access in a hotel bathroom and still be unnecessary for getting through a US checkpoint.

 With both tests in mind, treat them as bag-shape evidence, not price guarantees. The *New York Times* result speaks to entry at security, while the *WIRED* roundup speaks to post-security packing. Before buying any purpose-built kit, re-check current shelf prices at the exact retailer you plan to use, since availability can change between now and your trip. Do not pay for "TSA-approved" labeling alone — compare the internal layout against a plain quart zip-top bag using the exact items you intend to pack.

 For a US–Europe round trip where you can live with 100ml containers, the test-backed baseline is to satisfy compliance first with the shape that already passed testing, and only add a second bag for organization if you actually need it. If a purpose-built kit cannot justify its price by that post-security need after passing that shape check, there is no test-based reason to upgrade for the sake of compliance. Keep that order of checks in mind before you spend money on any liquids kit.

## Kit vs Checked Bag: The Table

 The head-to-head comparison across trip lengths is straightforward: for travelers who can stay carry-on-only, the quart bag is the lower-cost option, because a single one-way checked-bag fee can exceed the entire kit cost before the return flight is even priced. A weekend hop, a two-week stay, and a multi-city itinerary all use the same comparison if the liquids fit the compliant containers and the bag stays in the cabin.

 Pull the exact fee from your carrier's website during booking—look on the specialty-baggage or fare-comparison page, not a blog summary. Transatlantic basic economy fares frequently exclude even the first checked bag, while standard economy on major carriers may include one; never assume either way, and recheck if you change fare class, route, or travel date. If the fee is bundled into the fare, record it as zero for this comparison rather than guessing.

| Line item | What to enter | Why it matters |
| --- | --- | --- |
| Compliant liquids kit | ~$15, or $0.18 zip bag | One-time kit cost |
| First checked bag, one way | Carrier's live fee | Often $30–$60 on transatlantic routes |
| Round-trip bag total | 2 × one-way fee | Shows the full fee exposure |

 With the stated $30–$60 each-way range, the kit is cheaper than one checked bag in one direction, and the gap widens on the return. That makes the quart bag the winner for carry-on-only travelers unless your itinerary forces at least two of the stated exceptions.

 Keep the comparison to cash costs only: do not fold in time at baggage claim, lost-bag risk, or convenience unless you are deliberately changing the decision rule. The table is meant to settle the fee question, not to relabel a preference as savings.

## Numbers That Decide It

 Use your own route as the worked example, but verify the live fare at booking. At checkout, look at the carrier's fee table: if a checked bag is not included, write down the displayed one-way fee as line item A. That single number is the comparison point for the whole section, because the question is whether one direction of bag fees costs more than the entire liquids kit.

 Checkpoint 2 is the kit build. As tested above, the best performer in the New York Times' seven-bag test was an 18-cent quart zip-top bag. Adding a small set of reusable 100 ml travel containers brings the total to roughly $15 — verify current prices at your retailer before buying, since the 18-cent figure is a test result, not a guaranteed shelf price. That cost is one-time and reusable for every future trip, so it does not scale with trip length or number of flights.

 Checkpoint 3 is the cost of being wrong in either direction. If you pack a container above the 100 ml limit or a bag that will not close, the kit can fail at the checkpoint; the downside is line item A plus delay, and repeating the same mistake on the return doubles that cost. If you instead check a bag for liquids that would have fit in 100 ml containers, you pay line item A for a problem the kit already solves.

 Compare line item A to about $15. With checked-bag fees commonly in the $30–$60 range each way, one direction can exceed the kit cost; verify your carrier's current fee table rather than assuming. If your displayed fee is at or below about $15, the arithmetic changes and you should recalculate from the same checkpoints — the kit is only the default when line item A is larger than the kit cost.

 The decision is therefore simple but conditional: carry-on-only with the cheap kit when line item A is larger than the kit cost and your itinerary does not force at least two of the exceptions in the reader rule. If it does force two, the kit is no longer the mathematically superior default, even though the $15 build remains reusable.

## Copy-Usable Carry-On Checklist

 This section is the reusable pre-booking artifact: four lines you run before every transatlantic purchase. It does not redo the cost comparison; it records the facts that decide whether the kit or a checked bag wins for your itinerary. Save it with your booking notes and fill it from carrier pages and your packing list.

 Line 1 is the pivot. If the first checked bag is included, the kit question is usually settled in favor of carry-on convenience; if it is not, write the fee each way exactly as the carrier lists it at booking and compare that with the kit cost you have already priced. Do not estimate from memory or from a previous trip.

 Line 2 is the stop rule. An empty list, or a list that travel sizes can satisfy, means you check the quart-bag box and stop; there is no need to continue to lines 3 and 4 unless your itinerary has a connection or a planned purchase. If the list is nonempty, keep it visible while you price workarounds.

 Lines 3 and 4 prevent late surprises. Line 3 names the connecting EU airport and confirms its 100 ml rule, because a transfer can impose screening even when your first leg did not. Line 4 forces a decision before booking on return-trip purchase weight risk—wine, oils, full sizes—so you do not discover at the airport that your carry-on plan has become a checked-bag plan.

 Use the checklist as a trigger, not an automatic verdict. The reader rule still stands: book carry-on-only with the kit unless at least two of the three forcing conditions are true. If only one is true, price the workaround—decanting, shipping, or a single checked bag on the return—before paying for a round-trip checked bag. Re-run all four lines when fares change, a carrier updates its fee table, or your packing list changes.

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## What to do next

| Step | Action | Why it matters |
| --- | --- | --- |
| 1 | Default to carry-on-only with the roughly $15 TSA-compliant liquids kit on US–Europe round trips where 100ml containers are acceptable. | It costs less than one $59 checked bag, and the best of the seven tested bags costs $0.18. |
| 2 | Check whether your itinerary requires liquids over 100ml; if so, count it as one exception. | The rule changes only when at least two of the three exceptions apply. |
| 3 | Check for a budget-carrier leg with no included cabin bag; if present, count it as a second exception. | A no-included-cabin-bag leg can force a paid bag even with a compliant kit. |
| 4 | Check whether you were already going to pay for a checked bag; if yes, count it as the third exception. | An already-planned checked bag changes the comparison against the kit. |
| 5 | Before every booking, re-check the carrier's current bag fee table, including transatlantic basic economy bag inclusion by carrier and fare class. | Checked bag fees are $30–$60 each way and inclusion varies. |
| 6 | If two or more exceptions apply, pay for the checked bag; otherwise stay carry-on-only with the kit. | This applies the canonical decision rule for this route. |

## Frequently Asked Questions

 **What checked bag fee range should I expect on US–Europe routes?**

 Checked bag fees are $30–$60 each way; verify your carrier's current fee table.

 **How cheap was the best of the seven tested TSA-compliant liquids bags?**

 The New York Times tested seven TSA-compliant liquids bags, and the best one costs 18 cents.

 **Will a partially empty bottle larger than 100ml pass through TSA?**

 A bottle that is larger than 100ml will not be accepted, since it is your container size, not the amount of liquid left inside, that gets you through security.

 **What are the exact 3-1-1 limits for containers?**

 Each container must be 100ml (3.4 oz) or less, all of those containers must fit in one quart-size clear bag, and only one such bag is allowed per passenger.

 **When should I avoid booking carry-on-only?**

 Book carry-on-only unless your itinerary forces at least two of three listed exceptions: liquids over 100ml, a budget-carrier leg with no included cabin bag, and "a checked bag you were" as stated in the rule.

 **For which trips is the roughly $15 TSA-compliant liquids kit vs checked bag comparison valid?**

 The thesis applies to US–Europe round trips where 100ml containers are acceptable.

## Quick answers

| How much does a roughly $15 TSA-compliant liquids kit cost compared to a checked bag on US–Europe routes? | A roughly $15 TSA-compliant liquids kit costs less than one $59 checked bag on US–Europe routes. |
| --- | --- |
| What range are checked bag fees on US–Europe routes? | Checked bag fees are $30–$60 each way. |
| How much does the best of seven tested TSA-compliant liquids bags cost? | The best of seven tested TSA-compliant liquids bags costs 18 cents. |
| What is the container size limit under the 3-1-1 rule? | Each container must be 100ml (3.4 oz) or less. |
| When should you book carry-on-only according to the guide? | Book carry-on-only unless your itinerary forces at least two of three listed exceptions. |

Canonical: https://www.mightytravels.com/2026/11/carry-on-liquid-limits-15-tsa-kit-vs-3060-checked-bag-fees/
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