Every measurement on this site came from somewhere, and this is the page where we show the source.
We publish two kinds of number. One is a bag: how big it is on the outside, what it weighs, how much it holds. The other is a rule: what an airline says it will carry in the cabin and in the hold. Those two disagree often enough that most of the trouble people have at a boarding gate lives in the gap between them.
What follows is how we take both measurements, what we do when a figure is missing, and how often we go back and read the source again. If you are a reporter, a brand, or a reader who wants to argue with one of our numbers, every airline row carries the URL its figures came from and the date attached to that row.
Measure your bag the way we do
Start with three outside measurements. Take them with the bag empty, standing on its wheels, handle down, across the widest point of each face. Then check them against the six boxes below, which are the cabin and hold standards that turn up most often across the 68 airlines we track.
Does your bag clear the common standards?
The six standards we test against
- Personal item boxThe most common under-seat limit. 16 carriers, including Lufthansa and Iberia.
- European cabin boxThe widest single standard in our set. 14 carriers, including Lufthansa, SWISS and Air Canada.
- US cabin boxThe box most carry-on bags are built to. 12 carriers, including American, JetBlue and Qantas.
- Narrow cabin boxDeeper but 5 cm narrower. 9 carriers, including Air France, KLM and LATAM.
- Shallow cabin boxThe tightest depth in wide use, and gate-gauged. 5 carriers: Ryanair, Vueling, Icelandair, Air India, Korean Air.
- Checked bag standardThe three sides added together. 53 carriers publish it as 62 in or 158 cm. We test the tighter of the two, which is 62 in converted: 157.5 cm.
How we measure a bag
A gate sizer is a metal box. It has no opinion about which part of a bag is structural, so neither do we.
The outside, not the inside
Every dimension we publish is taken across the widest point of the face, with the bag empty, standing on its wheels, handle down. Wheels count. Handle housings count. Feet, bumpers, and the bulge a front organizer makes when it is loaded all count.
That is not always what a maker publishes. Four of the 49 bags in our size database were not measured on the outside, and each one says so on its own row: two are interior figures, one is an unexpanded case that grows past its own limit once the expansion zip is open, and one was measured packed. A green check beside an interior number overstates the case, so those four carry the basis alongside the verdict rather than a bare tick. Our step by step version of the same routine lives in how to measure luggage, with the hard-shell case treated separately in how to measure a suitcase.
Weight, empty and packed
We publish empty weight, because it is the only weight that belongs to the bag rather than to the trip. Nineteen of the 49 bags in our database have no published weight and the field stays blank instead of getting an estimate.
Packed weight is the number that gets you charged, and it is yours, not the bag’s. Fourteen of the 68 airlines we track publish no cabin weight limit at all. Three of them say what they use instead: British Airways, Air Canada and WestJet all run a lift test, so if you cannot get the bag into the bin unassisted it goes in the hold. The other eleven publish nothing on cabin weight and say nothing about lifting. The 54 carriers that do publish a figure vary widely, and several apply it across the carry-on and the personal item together instead of per bag. ANA is the clearest case, where 10 kg covers both items at once, which is what catches people carrying a heavy laptop bag.
Capacity in liters
Capacity is the softest number we publish and we treat it that way. Makers measure it differently: some fill only the main compartment, some count every pocket, some quote a nominal figure for a whole size family. We repeat the maker’s figure, we say it is the maker’s figure, and we never turn three dimensions into a volume and call it capacity. Twenty-three of the 49 bags have no published capacity, and that field stays blank too.
Where the numbers come from
Most of the dimensions in our size database are the maker’s own external figures, recorded with the basis attached so you can see what was measured. Where we have the bag in hand we take the three measurements ourselves with a rigid tape and a square, and weigh it empty on a flat digital scale checked against a known mass. The row has one limit you should know about. The basis field records what was measured, outside the bag or inside it, unexpanded or packed. It does not record who measured it, and the gear database carries no field for that today.
The linear sum is always ours. We add the three sides instead of copying a linear figure off a spec sheet, because a spec sheet’s linear number is often the sum of the interior. The arithmetic is simple enough to check by hand, and how to calculate linear inches walks through it.
What we record, and what we do when it is missing
A missing number is a fact about the source, not a hole to fill. We do not infer a dimension, we do not round a weight into existence, and we do not print a zero where a figure should be. A field we do not have is empty, and the row says why.
Every field we publish
| Field | What it means | When it is blank |
|---|---|---|
| Outside dimensions | Height, width and depth at the widest point of each face, wheels and handle housing included | The only published figure is an interior or a nominal size. 236 of the 290 bags we researched had no usable size and none of them got an estimate |
| Basis | Whether the figure was taken outside the bag, inside it, unexpanded, or packed | Never. 45 of our 49 measured bags read external, and the other 4 name what they read instead |
| Linear inches | The three outside dimensions added together, recomputed by us on every build | Never, when the three dimensions exist. We recompute rather than copy |
| Empty weight | The bag on a scale with nothing in it | The maker publishes no weight. Blank on 19 of 49 bags |
| Capacity | Liters, exactly as the maker states them | The maker publishes no capacity. Blank on 23 of 49 bags |
| Cabin limit | The airline’s own published cabin box, in the units the airline uses | The carrier publishes a linear sum and no per-side limit, as Singapore Airlines does |
| Cabin weight | The airline’s own published cabin weight cap | The carrier publishes no cabin weight. Blank on 14 of 68 airlines, three of which run a lift test instead |
| Checked limit | The airline’s own published linear sum for a hold bag | The carrier publishes a per-bag box instead of a sum. Blank on 10 of 68 airlines |
| Source | On an airline row, the exact page the figures were read from | Never on an airline row: 68 airlines, 68 separate sources, one per carrier. Bag rows carry no source field yet, only a basis and a link to our own review |
| Verified | The date on an airline row. Today that is the date the airline set was built; from the first re-read on, it is the day we last opened that carrier’s page | Never on an airline row. Bag rows carry no date yet |
Why the published numbers disagree
Three habits account for almost every conflict a reader runs into, and not one of them is a lie.
Airlines publish centimeters, then convert them loosely
Almost every carrier outside North America writes its limit in centimeters and adds an inch conversion for the English-language page. The conversion is where the drift starts. Across our 68 carriers, 126 published cabin boxes carry both a centimeter figure and an inch figure, counting the carry-on and the personal item separately. That is 378 sides we can check. Divide each centimeter side by 2.54 and 50 of the 378 disagree with the airline’s own inch figure by 0.2 to 0.5 inches. Those 50 sit on 22 airlines, and on 42 of them the inch column is the more generous of the two, which means a reader working in inches is told a bag clears a box the centimeter figure says it does not.
The gap is small and it always runs in the direction that costs money. So we compute every fit from the centimeter column, including the checker at the top of this page, and we show inches as a conversion rather than as the rule.
One box, written three ways
55 x 40 x 23 cm is a single box. Across our set it is written as 21.5 x 15.5 x 9, as 21.7 x 15.7 x 9, and as 21.7 x 15.7 x 9.1, depending on which airline is doing the rounding. Put those rows side by side and it looks like three different policies. It is one policy and three rounding habits, so we treat the centimeter box as the identity of the limit and the inch figure as a label on it. Where an airline’s own inch figure is the outlier, the row’s note says so.
Makers measure the case, sizers measure the bag
A maker measures the case. An airport sizer measures everything the case is wearing. Wheels add roughly one to two inches to the height of a spinner, and a recessed handle housing adds a fraction more. A bag sold as 22 x 14 x 9 that measures 23.5 x 14 x 9.5 on its wheels is not mislabeled by the maker’s own convention, and it is still too big for the box at the gate. That single difference is the most common reason a bag that should fit does not, which is why our numbers include the wheels and why the size visualizer draws bags and gate boxes at the same scale.
Some limits are not one number
Emirates publishes one checked limit on piece-concept routes and another on weight-concept routes, and for a traveler flying to or from the Americas it is the tighter of the two at 150 cm. Qatar Airways changes its checked limit by destination. Jetstar carries a rule dated 2 February 2027 that splits its cabin allowance into an overhead bag and an under-seat bag, published today alongside the rule in force now. A single figure per airline loses the answer that matters, so those rows carry the qualifier in full.
How the airline dataset is maintained
Sixty-eight carriers, one record each, and every record carries the page it came from.
One named source per airline
Every row stores the exact URL its figures were read from: a baggage page, a fare-conditions page, or where the site would not render, the filed contract of carriage. Sixty-seven of the 68 were read live off the carrier’s own site. The one that was not is PLAY, which has ceased operations. Its figures come from an archived snapshot, the row is flagged secondary-source, and it is kept out of anything that gives a reader advice.
A date on every row
Every airline row carries its own date, and the charts print it beside the carrier instead of as one site-wide line at the top. Today that date means one narrow thing. All 68 rows carry the same day, the day the set was built in a single research pass, which is not independent proof that each carrier’s page was opened again that morning. From the first re-read onward the dates separate and each one means the day we last opened that carrier’s own page. The field is per row from the start because a stamp covering a whole page tells you nothing about the row you are looking at.
The monthly re-read
Our commitment is to re-read every stored source URL on a monthly cycle, and the date at the top of this page is when the next pass is due. When a row still matches its source, the date moves and the figures stay put. When a row has moved, it gets the new figures and a new date. When a source URL stops resolving the row keeps its last known figures and drops to secondary-source, so you can see the source went away instead of finding a number with nothing behind it. The first re-read has not happened yet, which is why every row still shows the build date.
Stated confidence, and no third level
Every row carries a confidence value. Verified-live means the figures were read off the carrier’s own live page or its filed contract of carriage, which covers 67 of the 68. Secondary-source means they were not, and the row says where they came from instead. There is no third level, because there is no row in the set we could not source at all. We would rather ship 68 sourced airlines than 100 with a dozen guesses among them.
The same method on the other rules
Baggage rules are not the only published limits worth tracking. We maintain the compensation and liability rules the same way, with a source and a date on every row, in what airlines owe you for damaged luggage and in our older guide to compensation for lost or delayed luggage.
What we will not do
- Infer a missing dimension from a similar bag, a product photo, or a nominal size.
- Print a zero where a figure should be, or a blank cell with no explanation beside it.
- Average two disagreeing sources into a number neither of them published.
- Let an affiliate link change a measurement. The size of a bag is not an opinion.
- Carry a figure forward without a date attached to it.
Questions we get about these numbers
Do you measure every bag yourselves?
No. Where we have the bag, we measure it; where we do not, we publish the maker’s external figure. The gear database does not yet carry a field for which of the two a given row is, so treat every bag row as the maker’s external figure unless the review says otherwise. What the row always tells you is the basis, meaning what the tape was wrapped around.
Why does your figure differ from the maker’s?
Usually because the maker measured the case and we measured the case on its wheels. Occasionally because the maker published an interior figure. If a difference is bigger than either of those explains, tell us. We will re-measure and post the correction with a date on it.
Can I cite these numbers?
Yes. Link to the page you took the figure from and to this one, and quote the date printed beside the airline row instead of the page’s own updated line. Until the first monthly re-read that date is the build date of the first pass, and it says so here. After it, the row’s date tells your reader how old that specific number is, and if a figure moves the date moves with it.
What if an airline’s own page contradicts you?
The airline wins, and we want to know. Send us the URL. If the carrier has changed its published limit, we update the row, move its verified date and note the change. If the carrier’s own page contradicts itself, which happens more often than you would expect, we record both figures and say so on the row.
How often do these limits change?
Less often than the internet suggests. The boxes themselves are stable for years at a time. What moves is enforcement and the fee attached to it, especially among the low-cost European carriers, where the gate policy can change while the published box stays where it was. Aer Lingus is the sharp example: the box has not moved, and a 10 kg bag brought to a European gate without the paid carry-on option now costs 35 EUR to put in the hold.
The rest of the toolkit
This page is the method. The tools that run on it are the carry-on size chart for all 68 airlines, the 62 linear inches chart and calculator for checked bags, the luggage size visualizer for seeing a bag and a gate box at the same scale, the gear database of every bag we have measured, and damaged luggage claim rules for what happens when the bag comes back broken.
If you would rather read than click: how to measure luggage, how to measure a suitcase, how to calculate linear inches, and the carrier-specific case in Southwest carry-on size. For bags we have measured and would actually pack, start with the best carry-on luggage and the best personal item backpacks.