It is a good plan to measure the exact dimensions of your carry-on luggage before boarding your flight. If it is over an airline’s limit, you may have to check your bag and pay checked baggage fees. Additionally, it may not fit into the overhead bin, especially if you’re among the last to board and the available bin space is taken.
All 3 dimensions – length, depth and width – of your carry-on luggage must be measured. The extrusions – handles, straps, and zippered compartments – should be included in the measurements for an accurate estimate.
Most airlines require that carry-on luggage should have a combined linear length of less than 45 inches.
Be prepared – as airlines continue to boost their revenue through ancillary fees, they will increasingly monitor the weight and size of carry-ons.