How to Measure Your Carry‑On Bag (Correctly)
At a glance: Measure external length × width × height (wheels and handles included). If an airline uses a single “linear” limit, add L + W + H.
What counts toward size
Unless your airline states otherwise, use external dimensions—that means wheels, side pockets, and the top handle are included. Telescoping handles count at their lowest stored position.
Tools you’ll need
- Flexible tape measure (preferred) or a rigid ruler
- Flat wall or door frame to align a straight edge
- Notepad (or your phone) to record numbers
Step‑by‑step measurement
- Prepare the bag — Empty or pack lightly so bulges don’t distort measurements. Close all zippers.
- Length (L) — With the bag upright, measure from the floor to the topmost point (usually the top handle housing).
- Width (W) — Measure the side‑to‑side distance at the widest point (include side pockets).
- Height (H) — Rotate the bag and measure front‑to‑back depth at the thickest area (include wheels).
- Record the largest values — Soft‑sided bags compress, but use the uncompressed dimensions for policy comparisons.
Tip: If your bag has rounded corners, measure to the farthest edge, not the seam. Airline sizers use straight edges.
Linear dimensions (L + W + H)
Some airlines publish a single “linear” maximum (e.g., L + W + H ≤ N). Add your three measurements and compare the sum to the airline’s limit. If your sum is equal to or below the posted maximum, you’re within policy.
Personal item sizing
Under‑seat items are smaller than carry‑ons and must fit beneath the seat in front of you. Limits vary by airline and aircraft. Check your airline’s posted size and use the same method above to measure.
Record & check your measurements
| Measurement | Inches | Centimeters |
|---|---|---|
| Length (L) | ____ in | ____ cm |
| Width (W) | ____ in | ____ cm |
| Height (H) | ____ in | ____ cm |
| L + W + H | ____ in | ____ cm |
Switch units in the checker if needed—conversions use 1 inch = 2.54 cm.
Common mistakes to avoid
- Measuring without wheels and handles
- Using internal/packing dimensions instead of external size
- Reporting the smallest side rather than the widest point
- Ignoring airline‑posted linear maximums