To measure your Ryanair bag in 2026, you must ensure it fits within the strict dimensions of 40 x 20 x 25 cm for a "Small Personal Bag" or 55 x 40 x 20 cm for a "10kg Check-in/Carry-on Bag." The best way to measure is to use a tape measure and include wheels, handles, and side pockets in the total length. Ryanair is notorious for using metal "sizers" at the boarding gate; if your bag doesn't slide easily into the bin, you will be charged a "gate-check" fee of approximately €/£46 to €/£70. A top 2026 tip is to use a soft-sided backpack rather than a hard shell for your personal item, as you can often "squish" a soft bag into the sizer if it's slightly overfilled. Always weigh your bag at home as well, as the 10kg limit is strictly enforced at the check-in desk, and overweight fees are calculated per kilogram, which can quickly exceed the cost of the flight itself.