How we check a bag
This page states the rules the site actually runs on. Where a rule is imperfect, we say so rather than round it up into a confident answer.
1. Where a number comes from
Each allowance is copied from a published page together with four things: the URL, the page title, a verbatim excerpt, and the date it was collected. Where the airline publishes the figure itself, that page is the source. Of the 193 pages cited, 183 are the airline's own page and 10 are classified as community sources — including one aggregator page, which is labelled as such on every row that uses it. Nothing is inferred from a photo, a forum post, or another airline's similar aircraft.
Currently 370 allowances from 155 airlines, drawn from 193 pages of which 25 have been re-read against the publisher's own page.
2. "Collected" is not "verified"
These are separate states and the site keeps them separate:
- The figure has been collected, with its excerpt and date.
- The page it came from is published by the airline itself, not by a third party.
- The excerpt has been read back against the live page and still matches.
- The rule has been checked line by line by a person and recorded as verified.
- Only then may it back a definite conclusion.
Today: 0 of 155 airlines have reached state 4 — so every airline row is still flagged as pending review. Reaching state 2 or 3 does not promote a rule to state 4; a source page can be live, reachable and correctly quoted while the rule built on it remains unconfirmed.
3. How a bag is compared
The three dimensions of your bag are sorted largest-first, and so are the airline's. Then each axis is compared in turn, and the weight and piece count are checked separately. Sorting both sides first means the answer does not depend on whether an airline prints its limit as length × width × height or height × width × length — an axis-order difference is a labelling difference, not a size difference.
Your input is validated before any comparison: a missing value, zero, a negative number or a non-numeric entry produces "Not enough info", never a pass. A bag is not accepted because we failed to read its size.
4. Four possible answers
- Fits — every published limit is met. If the rule itself is still pending review, the answer is shown alongside a Preliminary marker.
- Borderline — the bag is at or within rounding distance of a limit, so a small measurement error changes the answer. Not a reassurance.
- Too big — at least one published limit is exceeded, and the answer names which one.
- Not enough info — the airline has not published the figure needed to answer, or the input could not be used. This is a real answer, not a failure state.
These four are not a description of a tool's error handling; they are what the rules themselves produce. A worked version, with counts for one common bag across every airline we cover, is in why a bag check has four answers.
5. When several rules could apply
Many airlines publish different limits per cabin, fare, route or aircraft. Two rules govern how those are used:
- With no conditions selected, only an allowance that applies to every ticket may answer. If an airline publishes conditional limits and no unconditional one, the answer is "Not enough info" and the site lists which conditions are missing — we never quietly answer with the most generous tier.
- With conditions selected, a rule answers only if every condition you selected matches it. No match means no rule, not the nearest one.
6. What we refuse to do
- We do not fill an unpublished weight, dimension or piece count with an estimate or a sibling airline's figure. Blank is a value.
- We do not silently correct an airline's own contradiction. If a page states dimensions whose sum exceeds its own linear limit, the numbers stay as published and the conflict is flagged on the rule page.
- We do not turn a comparison into a recommendation. There is no score, no ranking and no "best airline" — only what each airline publishes.
- We do not treat a page being reachable as proof that a rule is current. Page content changes; verification is a dated, recorded act.
7. Corrections
If a figure here disagrees with the airline's page, the airline is right. Report it and the record is re-collected, not patched. Report a wrong figure · Editorial policy