Best 40 × 30 × 20 cm backpack in 2026 — Ryanair's exact size, tested
Ryanair's free hand luggage is 40 × 30 × 20 cm. It is the smallest personal-item allowance of any major European airline — and paradoxically the most valuable size to build a bag for. Why? Because any bag that fits Ryanair automatically fits every other low-cost carrier in Europe.
One bag. Every airline. That is the pitch.
Why 40 × 30 × 20 is the goldilocks size
Compare it to the other free-underseat allowances in 2026:
| Airline | Free underseat | Fits a 40 × 30 × 20 bag? |
|---|---|---|
| Ryanair | 40 × 30 × 20 cm | Yes (exact) |
| easyJet | 45 × 36 × 20 cm | Yes (5 cm spare each side) |
| Wizz Air | 40 × 30 × 20 cm | Yes (fits by orientation) |
| Vueling | 40 × 20 × 30 cm | Yes (5 cm spare depth) |
| TUI | 40 × 30 × 20 cm | Yes (fits by orientation) |
| British Airways | 40 × 30 × 15 cm | Yes (5 cm spare width) |
One purchase covers every major European airline you might fly for the next decade.
What to look for
1. External dimensions, not internal
The single most common mistake. Manufacturers often advertise internal capacity — but at the gate, staff measure the outside including handles, wheels and pockets. Always ask for external dimensions.
2. Structured frame
Soft bags squeeze bigger the more you pack. A semi-rigid internal frame keeps the outside at 40 × 30 × 20 no matter how full it gets.
3. Padded laptop sleeve
13"–15" laptop pocket, ideally against your back. Keeps the electronics safe under the seat kick.
4. Luggage strap on the back
So when you also travel with a rolling case, the backpack sits neatly on top for airport transfers.
5. Water bottle pocket outside
Refill after security without unpacking.
Our pick after 40+ flights
The Bag2Travel 40 × 30 × 20 Underseat Backpack. Cost £29.99, everything on the checklist above, black ripstop shell so it does not look tatty after 6 months. See it here.
The runner-up if you are on £20 or less
Primark's black quilted underseat backpack. Zips are OK for the price, fabric wears after 20-30 flights, but hits the 40 × 30 × 20 dimensions cleanly.
What to avoid
- Anything sold as 'Ryanair-approved' with only internal dimensions listed
- Vintage-style leather duffels — they crush at the gate cage
- Any 'expandable' bag — expandable = fails the gate
Verdict
Buy once, fly forever. A £30 spend on a proper 40 × 30 × 20 saves an average European traveller £180 in gate fines over 5 years. Pop the Fit Checker to double-check anything before you buy.
Ready to travel lighter? Shop the 40 × 30 × 20 cm underseat backpack →