How to use the in-cabin pet weight checker
The first gate you hit when flying with a pet is whether the two of you clear the in-cabin allowance. Airlines count the animal and the carrier together, and they also cap the carrier size. Enter your pet weight, the empty carrier weight and the carrier’s length, width and height, then the matching limits printed in the rules of the airline you are booking. Leave the weight limit blank if the airline sets none, which is common among US carriers.
The arithmetic is plain: combined weight = pet weight + carrier weight, and room left = the airline limit minus that total; for size, each of length, width and height is compared with its own maximum. Everything is compared and shown to two decimals. When the total equals the limit exactly the result reads 0.0 and still counts as meeting it. Airlines set these numbers themselves around the IATA live animal transport guidance, so there is no single figure to hard-code and every limit here is an input. Current as of October 2026.
This tool does not store airline-by-airline allowances and does not cover breed restrictions, temperature embargoes or the cap on pets per cabin. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently Asked Questions
Yes. Most US airlines limit the carrier by length, width and height so it fits under the seat in front, and many set no weight limit, while some do cap pet plus carrier weight. The figures vary by airline, aircraft and cabin, so this checker never assumes a limit and asks you to type it in.
Checked or cargo transport has its own rules, advance approval, and sometimes breed or temperature restrictions. Confirm it with the airline before you book.
Measure length, width and height separately at the widest points, including any wheels or handles that stick out. Each one is compared with the matching airline maximum, because the carrier has to fit the under-seat space on every side.