Under Seat Cabin Bag – Sizes, Rules & Best Bags 2025
Flying with only an under seat cabin bag can save both time and money. But the rules vary widely between airlines, and getting the dimensions wrong often leads to unexpected fees at the gate. Understanding the exact size allowances for your carrier is the first step toward stress-free travel.
Airlines have been shrinking their free personal item allowances in recent years, and 2025 is no exception. While some carriers offer generous space under the seat, others enforce strict limitations. Knowing which bag fits where can make the difference between a smooth boarding experience and an additional charge.
This guide breaks down the standard dimensions, the specific rules for major low-cost airlines, and what to look for when buying an under seat cabin bag in 2025.
What are the standard dimensions for an under seat cabin bag?
Under Seat Cabin Bag at a Glance
- Standard dimensions: 40×20×25 cm for many mainstream airlines
- Ryanair personal item: usually 40×20×25 cm (must fit under seat)
- EasyJet underseat: 45×36×20 cm maximum (free underseat allowance)
- Other sizes: 40×30×20 cm used by some carriers (e.g., Jet2)
Key Insights
- Under seat bags are typically smaller than overhead cabin bags, designed to save airlines on gate‑check fees.
- The 40×20×25 cm size is the most common global standard, but budget carriers often have unique requirements.
- Many travellers mistakenly buy 45×36×20 cm bags thinking they fit all airlines – this size only works for EasyJet and a few others.
- Soft‑sided under seat bags are more flexible for tight spaces than hard‑shell cases.
- A growing number of airlines are tightening personal item sizes in 2025.
Quick Facts: Under Seat Cabin Bag Sizes by Airline
| Airline | Dimensions | Type | Enforcement |
|---|---|---|---|
| Ryanair | 40×20×25 cm | Personal item (free) | Strict enforcement |
| EasyJet | 45×36×20 cm | Underseat (free) | Wheeled ok, but must fit gauge |
| Wizz Air | 40×30×20 cm | Personal item (free) | Soft bag recommended |
| Jet2 | 40×30×20 cm | Underseat (free) | Often measured |
| British Airways | 40×20×25 cm | Underseat (free) | Flexible up to 23×16×12 inches |
What does the 40×20×25 cm dimension mean?
A bag labelled 40×20×25 cm is 40 cm tall, 20 cm deep, and 25 cm wide. This is the dimension used by Ryanair and many other carriers including British Airways. It is also a common size for mainstream airline personal items. When buying, check that the listed dimensions include handles and wheels, as airlines measure the bag at its fullest.
What does the 45×36×20 cm dimension mean?
The 45×36×20 cm size corresponds to EasyJet’s free underseat allowance. It is wider and slightly taller than the Ryanair standard, offering more packing capacity. This size is less universal, so travellers who fly multiple airlines should consider whether they need a bag this large.
What does the 40×30×20 cm dimension mean?
This dimension is used by Wizz Air, Jet2, and other European carriers. It is a safe middle ground that fits many airlines, though it gives up the extra width of the EasyJet size. Many travellers opt for 40×30×20 cm when they want a single bag for various low‑cost airlines.
What size under seat cabin bag does Ryanair allow?
Ryanair’s free personal item allowance is exactly 40×20×25 cm, including handles, wheels, and any external pockets. The bag must fit easily under the seat in front of you. The airline enforces this strictly at the gate using a metal bag sizer, and a bag that is even slightly too large may be denied or subject to a fee. Ryanair also sells a larger cabin bag option on some fares, but the free under‑seat bag remains the 40×20×25 cm size.
Ryanair is known for using metal sizing cages at the gate. If your bag does not fit, you will be charged a fee — often £30 or more — and the bag will be placed in the hold. Always check that your fully packed bag meets the 40×20×25 cm limit before travelling.
Which airlines require 40×20×25 cm under seat bags?
Besides Ryanair, British Airways, Vueling, and Aer Lingus use the same 40×20×25 cm limit for their free personal item. Some US carriers have similar dimensions, though they often express them in inches (roughly 16×8×10 inches). Always verify the exact allowance on the airline’s website before purchasing a bag.
What size under seat cabin bag does EasyJet allow?
EasyJet permits a free under‑seat bag with dimensions of 45×36×20 cm. This is one of the more generous allowances among low‑cost airlines. The bag must fit under the seat in front, and wheels are allowed as long as the entire bag passes the sizing gauge. EasyJet does not publish a strict weight limit for this item, but it must be manageable for one person to lift and place under the seat.
Although EasyJet accepts wheeled bags up to 45×36×20 cm, many travellers prefer soft‑sided options because they compress more easily into the under‑seat space. Hard‑shell wheeled bags that are exactly at the limit may be rejected if they bulge or do not slide into the sizer.
Which airlines accept 45×36×20 cm under seat bags?
This size is primarily associated with EasyJet. Other carriers such as TUI and some smaller regional airlines may also accept it, but it is not a universal standard. If you mainly fly EasyJet, the 45×36×20 cm bag offers the most room. For multi‑airline travel, a smaller bag is safer.
What are the best under seat cabin bags to buy in 2025?
The best bag depends on which airline you fly most often. For Ryanair and similar carriers, a 40×20×25 cm bag from brands like Cabin Max, Samsonite, or Tripp is a reliable choice. For EasyJet, Aerolite Luggage and Tripp offer models specifically designed to the 45×36×20 cm limit.
What features should I look for in an under seat cabin bag?
- Lightweight construction: Every kilogram counts when you are carrying the bag.
- Padded laptop compartment: Many bags now include a sleeve for a 13‑ or 15‑inch laptop.
- Multiple pockets: Organisation helps you make the most of limited space.
- Sturdy handle and wheels: If you choose a wheeled model, ensure the wheels are robust and do not add bulk beyond the allowed dimensions.
- Compression system: Soft bags with straps can be cinched down to fit the sizer.
Are wheeled under seat cabin bags allowed on all airlines?
Not always. While EasyJet and British Airways allow wheeled under‑seat bags, some budget airlines discourage them because the wheels can take up space that could otherwise be used for a deeper bag. Ryanair does not explicitly ban wheels, but the bag must still fit the 40×20×25 cm gauge, which some wheeled models struggle to meet.
Can I use a backpack as an under seat cabin bag?
Yes. Backpacks are widely accepted as long as they stay within the airline’s size limits. Soft backpacks are often easier to squeeze into tight spaces than hard‑sided cases. Measure the backpack when fully packed to ensure it does not exceed the dimensions.
Where can I buy affordable under seat cabin bags online?
Major online retailers such as Amazon (search for “under seat cabin bag”), Cabin Max, Tripp, Samsonite, and Aerolite Luggage offer a wide range of options. Budget brands like it luggage and Trolley Joe also carry affordable models. Always compare the listed dimensions against your primary airline before purchasing.
When did airlines change their under seat bag policies?
- 2018: Ryanair reduces its free personal item size to 40×20×25 cm.
- 2020: EasyJet standardises its underseat allowance to 45×36×20 cm.
- 2023: Wizz Air expands weight limits but keeps the size at 40×30×20 cm.
- 2025: Several airlines begin using new bag‑size check tools at gates, increasing the likelihood of enforcement.
What is definitely known and what remains uncertain about under seat bag rules?
| Established information | Information that remains unclear |
|---|---|
| Ryanair’s personal item size is exactly 40×20×25 cm including handles and wheels. | Whether wheeled bags count as ‘personal items’ can vary by airline even within size limits. |
| EasyJet’s underseat bag allowance is 45×36×20 cm. | Some airlines (e.g., TUI) do not enforce strict dimensions for under seat bags. |
| Most airlines measure bag size with a gauge; soft bags can be squeezed slightly. | The exact tolerance (how much over is allowed) is rarely published and enforced inconsistently. |
| — | Bag weight restrictions often accompany size rules but are not always mentioned on product pages. |
Why does the distinction between cabin bag and under seat bag matter?
Understanding the difference between a ‘cabin bag’ (which goes in the overhead bin) and an ‘under seat bag’ (a personal item) is critical to avoid unexpected fees. Many airlines allow only one free under‑seat bag and charge for a second larger cabin bag. The pressure on airlines to maximise ancillary revenue has led to shrinking under‑seat allowances – a trend that continues in 2025. Consumer demand for wheeled under‑seat bags has increased, yet many airlines discourage wheels due to limited space under the seat. The rise of ultra‑light travel is pushing passengers to maximise every centimetre of their under‑seat allowance.
Before you buy, check the airline’s latest policy. Rules can change, and what worked last year might not work today. For more tips on preparing for your trip, read our guide on London to Luton Airport – Cheapest, Fastest & Best Travel Options.
What do industry sources say about under seat cabin bags?
“The typical dimensions for under seat bags are 40 x 20 x 25 cm, but they may vary by airline.”
— Samsonite.co.uk, official product page
“These are the best underseat cabin bags, from chic carryalls to functional duffle bags, independently tested and reviewed.”
— CN Traveller, 6 March 2026
“Expertly designed to fit within EasyJet’s free underseat allowance.”
— Tripp.co.uk, brand‑specific claim
For independent expert reviews, see the full article by CN Traveller.
What is the bottom line for choosing an under seat cabin bag?
If you want maximum flexibility across airlines, choose a bag at or under 40×30×20 cm and make it soft‑sided if possible. If you mainly fly EasyJet and want more room, the 45×36×20 cm size is the better fit. Always check the latest dimensions on the airline’s website before you buy, and remember that overpacking can push your bag outside the allowed size. For peace of mind, consider Travel Insurance for Medical Conditions – UK Guide & Costs before your next trip.
Frequently asked questions about under seat cabin bags
Is there a difference between a cabin bag and an under seat bag?
Yes – ‘cabin bag’ typically refers to a carry‑on that fits in overhead bins (larger), while ‘under seat bag’ is a smaller personal item that must fit under the seat in front of you. Airlines often allow only one under seat bag for free and may charge for a second cabin bag.
How strict are airlines about under seat bag dimensions?
Strictness varies. Low‑cost carriers like Ryanair and EasyJet enforce dimensions at the gate using metal bag sizers. Premium airlines tend to be more lenient. A bag a centimetre or two over may be denied or subject to a fee.
Can I use a backpack as an under seat cabin bag?
Yes, as long as it fits the airline’s stated dimensions. Soft backpacks are often easier to squeeze into tight spaces than hard‑sided suitcases. Measure your backpack fully packed to ensure compliance.
Where can I buy affordable under seat cabin bags online?
Look at retailers like Amazon, Cabin Max, Tripp, Aerolite Luggage, and Samsonite. Budget options are available from brands like it luggage and Trolley Joe. Always compare dimensions against your airline.
What features should I look for in an under seat cabin bag?
Lightweight construction, padded laptop compartment, multiple pockets for organisation, a sturdy handle/wheels (if allowed), and a compression system. Check that the bag meets your primary airline’s dimensions.
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