Retain the original dimensions
A three-number specification is not always height, width and depth in that order. Store the numbers and the published axis labels together. Where labels are absent, keep them unknown rather than adding familiar labels.
A unit conversion is a separate display calculation. Show the original centimetres, millimetres or inches so a reader can recover what the source actually said.
Apply the correct comparison operation
A three-side sum, a longest-side cap and a three-axis box limit require different checks. A bag can pass a sum while exceeding an individual side; conversely, a longer narrow bag can be within a sum without matching a specified box.
| Rule form | Screening calculation | Remaining limitation |
|---|---|---|
| Three-axis limit | Compare each established side in a permitted orientation | Unknown labels or orientation permission prevent a confident match |
| Sum of three sides | Add all three measured outside sides | Does not create unpublished individual side caps |
| Longest-side limit | Compare the longest relevant side | Other size or storage requirements may still apply |
| A4 or A3 shorthand | Preserve the shorthand and known source context | No published three-dimensional depth is inferred |
Keep boundary language intact
Strictly smaller than and no larger than differ at the boundary. The Crypto.com Arena clutch record preserves smaller-than wording. JR Central's oversized rule uses a three-side sum over 160 cm through 250 cm and also publishes 161–250 cm wording; the record retains both descriptions.
Do not turn JR Central's sum range into a fictional height-by-width-by-depth box or invent a decimal gap between the descriptions.
Measure the same kind of object
Compare a packed exterior measurement with the relevant exterior rule. A manufacturer's nominal dimensions, an internal pocket measurement and a storage-rack design reference describe different things.
Deutsche Bahn's rack design dimensions are recorded as storage guidance, not as a maximum admission allowance. A numerical screen may help plan, but does not certify boarding or entry.
Sources and check dates
- Japan Airlines — official policy ↗Checked 2026-10-14
- Crypto.com Arena — official policy ↗Checked 2026-10-14
- JR Central / Tokaido Shinkansen — official policy ↗Checked 2026-10-14
- Deutsche Bahn — official policy ↗Checked 2026-10-14
- Rijksmuseum — official policy ↗Checked 2026-10-14