KLM Royal Dutch Airlines is generally known for being moderately strict with hand luggage, particularly on high-occupancy European routes. For 2026, the standard allowance in Economy Class is one bag (55 x 35 x 25 cm) and one personal item (40 x 30 x 15 cm), with a combined weight not exceeding 12 kg (26 lbs). Unlike some low-cost carriers, KLM does not always weigh every bag at the check-in desk, but they frequently use "sizing sizers" at the boarding gate. If the flight is full, gate agents will often proactively ask passengers to check their larger carry-on bags into the hold for free to ensure there is enough overhead space for everyone. However, if your bag is visibly oversized or significantly over the weight limit, you may be charged a "gate bag fee." To avoid issues, travelers are encouraged to join the Flying Blue loyalty program, as higher-tier members often receive more leniency. Always ensure your personal item fits under the seat in front of you, as this is the rule agents are most likely to enforce strictly during the boarding process.