The 25cm bag that fits every airline sizer — measured 25×17×14cm

Short answer: a bag measuring 25 × 17 × 14 cm clears every major airline’s published personal-item limit, including the 15 cm depth caps at Lufthansa, SWISS, Air France, KLM, British Airways and Iberia. The “universal free box” of 40 × 25 × 20 cm that circulates on other sites is wrong — the real figure is 40 × 25 × 15 cm.

Most "personal item" advice tells you to buy a bag and hope

We did the opposite. We took our own bag — the Jelkin 25 Cloud — and measured it against every major airline's published personal-item limit. It is 25 × 17 × 14 cm externally. It fits every sizer we checked, with margin. Here is the math, and why the popular "universal box" number you will find on other sites is wrong.

The real universal free box is 40 × 25 × 15 cm — not 40 × 25 × 20

To build a bag that is free on every airline, you take the strictest limit in each dimension across all carriers, not the average. Here is what the official baggage pages actually say (checked October 2026):

Airline	Personal item limit (L × W × D)	Depth cap
Ryanair / Wizz Air	40 × 30 × 20 cm	20 cm
Lufthansa / SWISS / Austrian	40 × 30 × 15 cm	15 cm
British Airways	40 × 30 × 15 cm	15 cm
Air France / KLM	40 × 30 × 15 cm	15 cm
Turkish Airlines	40 × 30 × 15 cm (4 kg)	15 cm
Eurowings	40 × 30 × 25 cm	25 cm
United (Basic Economy only free item)	17 × 10 × 9 in = 43 × 25 × 23 cm	23 cm, but width is the bind at 25.4 cm
American / Alaska / JetBlue	18 × 14 × 8 in = 46 × 36 × 20 cm	20 cm
EasyJet	45 × 36 × 20 cm	20 cm

Take the minimum of each column and you get the box that clears all of them: 40 cm (length, set by Ryanair/Wizz) × 25 cm (width, set by United's 10 in) × 15 cm (depth, set by Lufthansa/BA/AF/KLM/Turkish).

Our bag, measured: 25 × 17 × 14 cm

The Jelkin 25 Cloud is a structured (sellier) shearling bag. Its external dimensions are 25 × 17 × 14 cm. Orient the longest side (25 cm) along the sizer's length:

• Length 25 cm ≤ 40 cm ✓
• Width 17 cm ≤ 25 cm ✓
• Depth 14 cm ≤ 15 cm ✓ (1 cm of margin)

It clears every airline's personal-item frame, including the strict European 15 cm depth ones. Because it is soft-structured rather than wheeled, it does not lose volume to handles or wheels — those are exactly what push a roller over the line.

What actually fits inside the 25 cm bag

External size is only half the story; usable space is what you pack. Measured against real daily carry:

• A phone up to 6.7 inches
• A full-size wallet (not just a cardholder)
• Keys, a compact, a lipstick
• Sunglasses in a hard case
• A paperback or an iPad mini

That is a genuine under-seat day bag, not a pouch.

Why the 25 cm width is the number that matters

United's personal item is the narrowest at 10 in = 25.4 cm wide. Anything at or under 25 cm clears it. Our 25 cm is right at that line and still passes. If a bag is even 26–30 cm wide (most "personal item" totes), it is fine on Lufthansa/Ryanair but can be challenged on United.

The catch nobody mentions: sizers include handles and wheels

Every airline measures including handles, wheels and hardware. A wheeled underseater at the same external stamp always carries less and risks failing the frame. A soft structured bag like ours compresses slightly and drops in cleanly. This is why we build to the conservative 15 cm depth instead of the 20 cm the looser guides suggest.

Frequently asked

Is a 25 cm bag big enough for a 13-inch laptop?

Usually no — a 13-inch laptop is about 30 × 21 cm and will not lie flat in a 25 × 17 cm bag. Use a separate laptop sleeve in your carry-on, or pick a tote. (We cover this separately.)

Will Ryanair measure my bag?

Yes. Ryanair and Wizz Air use a metal sizer at the gate; the bag must drop in including handles. At 25 × 17 × 14 cm ours does.

Does the depth really have to be under 15 cm?

Only on Lufthansa-group, British Airways, Air France, KLM and Turkish. On Ryanair/EasyJet/American the limit is 20 cm. Building to 15 cm clears all of them.

Method note

Bag dimensions are from the product specification. Airline limits are from each carrier's official baggage page as of October 2026 and include handles and wheels. Limits change; always confirm against your booking before flying.

Questions people ask

What is the strictest personal-item limit in 2026?

Depth, not length. Six European carriers — Lufthansa, SWISS, Air France, KLM, British Airways and Iberia — cap the under-seat item at 40 × 30 × 15 cm, which is tighter than the 20 cm depth allowed by Ryanair, easyJet, Transavia, Vueling and Wizz Air.

Does a 25 × 17 × 14 cm bag fit Ryanair’s free sizer?

Yes. Ryanair’s free under-seat bag is 40 × 30 × 20 cm, so a 25 × 17 × 14 cm bag passes on all three axes with room to spare. It only has to drop into the sizer, which is easier with a soft bag than a rigid one.

Why do other sites say 40 × 25 × 20 cm?

Because they average the limits instead of taking the strictest one in each dimension. A 20 cm-deep bag is rejected at the six carriers that cap depth at 15 cm, so 40 × 25 × 20 cm is not a universal box. 40 × 25 × 15 cm is.

Do these limits include handles and wheels?

Yes. Where a carrier publishes a personal-item size, the figure covers the outside of the bag, handles and wheels included.

Check a specific bag: the airline personal item size checker runs 19 carriers side by side. For the other half of the problem — how much actually fits inside — see why external dimensions lie about capacity. The three allowances that decide most trips are Ryanair, Lufthansa and easyJet, and the rules behind them are here.