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If you fly with only a backpack as hand luggage, you want to be sure your bag fits in the overhead bin or under the seat. Rules differ by airline and even by fare, so choosing the wrong size can mean unnecessary extra charges. In this guide, you’ll find the most important dimensions per airline, practical tips for choosing the right backpack as hand luggage, and concrete ByMetz suggestions that match well-known size categories exactly. Whether you fly with Ryanair, KLM, Transavia, TUI, Wizz Air, Vueling or Corendon: with the right size and layout, you travel lighter, faster and without surprises. Looking for an under-seat model? Check out the Hand luggage 40x30x20 collection.

Allowed sizes by airline

The guideline sizes below help you choose straight away. Please note: conditions and fares change regularly. Always check the current rules with your airline, especially if you want to bring an extra or larger piece of hand luggage.

If you fly with Ryanair, never mix up the categories: the free small personal bag is 40 x 30 x 20 cm, while the 10 kg cabin bag is 55 x 40 x 20 cm. Checked baggage has different maximums again. If you buy a larger cabin item with other airlines, the sizes in the table apply to the overhead compartment. If you want to be sure your bag fits under the seat, also view our Underseaters. Not sure whether your backpack fits standard cabin requirements? Then look at Hand luggage 55x40x20. For a clear explanation of rules and allowed sizes, read the complete guide to hand luggage dimensions.

Why 35–40 liters is often the best choice

A backpack of around 35–40 liters makes optimal use of cabin size limits without overstuffing. Capacity doesn’t say everything, but as a rule of thumb, 35–40L fits well within 55 x 35 x 25 or 55 x 40 x 20 cm. It gives enough room for 3–5 outfits, toiletries in a 1-liter bag, shoes and a 13–15.6 inch laptop. If you choose a hand luggage backpack with suitcase-style opening, internal compression and a rear laptop compartment, you’ll pack more efficiently and get through security faster. For Ryanair’s small personal bag, 20–25L is more realistic — it goes under the seat and is ideal for ultralight city trips. For compact options that often work as hand luggage, check out our daypacks.

Travel pack or trekking backpack?

A travel pack is designed for travel with cabin limits in mind: rectangular profile, full suitcase-style opening, internal compression straps, multiple organization compartments and often a coverable carry system. You use every square centimeter more efficiently, which is crucial at 40 x 30 x 20 or 55 x 35 x 25 cm. Packing and unpacking also feels more like using a suitcase.

A trekking backpack is optimized for carrying comfort on trails: rounder shapes, top loading and external webbing. Great for hikes, but less efficient in an overhead bin and often more difficult at security because you dig from the top. If you mainly fly and take city or business trips, choose a travel pack. If you’re planning a mountain trek and only flying out and back, a well-compressible trekking backpack can work. Tip: use packing cubes and fill dead corners, so you comply more easily with strict airline measurements and keep your backpack as hand luggage neatly in shape. If you want to combine rolling and carrying, consider a backpack with wheels.

What to look for when choosing a hand luggage backpack

• Size and shape: matched to your airline and fare. Straight corners use the allowance better than round shapes.
• Weight: the lighter the bag, the more kilos remain for your contents.
• Access: a full suitcase-style opening is fastest at security and in the hotel.
• Laptop compartment: suitable for 13–18 inch, preferably separate and padded.
• Organization: front pockets for cables, liquids and travel documents.
• Compression: internal straps or external straps to reduce volume.
• Carrying comfort: adjustable shoulder straps, sternum strap and possibly hip belt.
• Material: water-repellent, sturdy zippers, lock-friendly runners.

Can you bring a suitcase and backpack as hand luggage?

That depends on the airline and your ticket. Some common situations:

• Ryanair: standard fare only includes one small personal bag of 40 x 30 x 20 cm. If you want an extra cabin bag in the overhead bin, choose Priority with a 10 kg cabin bag of 55 x 40 x 20 cm. A trolley plus separate backpack is only possible if one item fits exactly in the small personal bag category and the other is your 10 kg cabin bag.
• KLM: often 1 piece of hand luggage 55 x 35 x 25 cm + 1 accessory 40 x 30 x 15 cm. A small backpack can then count as the accessory, with your trolley or larger backpack as the main hand luggage item.
• Transavia: small item 40 x 30 x 20 cm under the seat. A larger cabin item 55 x 35 x 25 cm can be added for a fee or in a bundle. Combining both is only possible within your fare.
• Wizz Air: free small personal bag 40 x 30 x 20 cm. With WIZZ Priority, you can also bring 1 cabin bag 55 x 40 x 23 cm.
• TUI, Vueling, easyJet, Corendon: policy varies by fare. Check whether you may bring a small extra item alongside your cabin bag and which size applies.

Main rule: taking two items is only allowed if your fare permits it and each item falls within the correct category dimensions.

Best backpack as hand luggage by airline: ByMetz picks

• Ryanair small personal bag 40 x 30 x 20 cm: ByMetz 40x30x20 Hand Luggage Backpack. Fits under the seat and includes a 14-inch laptop compartment and USB port.
• Ryanair 10 kg cabin bag 55 x 40 x 20 cm: ByMetz 55x40x20 Hand Luggage Backpack, expandable to 55 x 40 x 25 cm for airlines that allow 25 cm. Use it at 55 x 40 x 20 cm for Ryanair.
• KLM 55 x 35 x 25 cm + accessory 40 x 30 x 15 cm: ByMetz 55x35x25 Hand Luggage Backpack for your main item and the ByMetz 40x30x15 → 40x30x20 as a compressed accessory.
• Transavia 55 x 35 x 25 cm or 40 x 30 x 20 cm: choose the ByMetz 55x35x25 for the overhead bin or the ByMetz 40x30x20 for under the seat.
• Corendon 55 x 40 x 25 cm: ByMetz 3-WAY Boarding Bag 55x40x25. Carry it as a backpack, shoulder bag or handbag.
• Wizz Air Priority 55 x 40 x 23 cm: the ByMetz 55x40x20 Hand Luggage Backpack stays within the size and makes optimal use of the height.
• Flexible between airlines: the ByMetz 55x40x20 expandable to 55x40x25 and the ByMetz 40x30x15 → 40x30x20 give you flexibility between strict and more generous rules without buying a new bag.

Packing like a pro: quick tips

• Use 2–3 packing cubes: shirts with shirts, underwear separate. That keeps the shape neat for under-seat or overhead use.
• Place liquids in a transparent 1-liter bag in the front pocket for fast security screening.
• Put your laptop close to the back panel in a padded compartment and place heavy items low and close to your back.
• Tighten internal compression straps and use external straps sparingly so you don’t exceed outer dimensions.
• Store charging cables in a cable organizer, and keep your passport and boarding pass in a separate easy-access pocket.

FAQ

Can a backpack be taken as hand luggage?

Yes, a backpack can be taken as hand luggage as long as it stays within the allowed dimensions of your airline and fare. With Ryanair, the free small personal bag is 40 x 30 x 20 cm. For an extra 10 kg cabin bag of 55 x 40 x 20 cm, you need Priority. KLM and Transavia use different sizes for main hand luggage and a possible accessory.

Does a backpack count as hand luggage or as an accessory with KLM?

With KLM, the usual allowance is 1 piece of hand luggage at 55 x 35 x 25 cm plus 1 accessory at 40 x 30 x 15 cm. So a small backpack can count as the accessory if it stays within 40 x 30 x 15 cm. Your main hand luggage may then be a larger backpack or trolley within 55 x 35 x 25 cm. Check your ticket type for possible exceptions.

Can you take a suitcase and backpack as hand luggage with Transavia and Ryanair?

Transavia: a small item of 40 x 30 x 20 cm is usually free, and a larger cabin bag of 55 x 35 x 25 cm can be added for a fee. Ryanair: standard fare only includes 40 x 30 x 20 cm, and an extra 55 x 40 x 20 cm 10 kg cabin bag is possible with Priority. So two pieces are only possible if each one matches the correct category and your fare allows it.

Is a trekking backpack allowed as a backpack for hand luggage?

Yes, provided the outer dimensions stay within the limits and nothing sticks out. In practice, a travel pack is usually more convenient: rectangular shape, suitcase opening, internal compression. With a trekking backpack, use packing cubes and keep external straps to a minimum so you don’t exceed 55 x 35 x 25 or 55 x 40 x 20 cm.

How many liters fit in 55 x 40 x 20 or 55 x 35 x 25?

Depending on shape and padding, you usually get around 35–45 liters of usable capacity. A tight travel pack without thick frames gets more liters out of the same size than a rounded trekking backpack. For Ryanair’s small personal bag 40 x 30 x 20 cm, 20–25 liters is often realistic.