The 115 cm "total" rule: what airlines that measure three edges instead of a box really mean

Short answer: ANA and JAL do not publish a personal-item box. They apply a 115 cm three-edge total to cabin baggage and ask that the personal item fit under the seat. A 25 × 17 × 14 cm bag sums to 56 cm — less than half the 115 cm total — so even under the total rule it is unambiguously fine; the only test left is the seat in front of you.

Box rule vs total rule

Most carriers quote a box: length × width × depth. A few quote a total: the sum of all three edges. The total rule is older and looser — it cares about the perimeter, not any single dimension.

Rule type	Example carriers	What it checks
Box (hard dimensions)	Lufthansa, Ryanair, American, United	each axis must be under the limit
Three-edge total	ANA, JAL (cabin baggage 115 cm)	sum of L + W + D
Under-seat test only	Delta, ANA, JAL (personal item)	fits under the seat, no printed number

Why the total rule is forgiving

A 25 × 17 × 14 cm bag totals 56 cm. Even a generously packed version at 28 × 20 × 16 cm totals 64 cm — still well under 115 cm. The total rule essentially never catches a personal item; it exists to stop people bringing a second large suitcase as "cabin baggage." For the personal item itself, the only real test is whether it disappears under the seat.

The honest caveat

"Under the seat" is judged by a human at the gate. A bag that is fine on paper can still be asked to go in the sizer if it looks oversized. The defence is the same dimension that wins everywhere else: keep it shallow. At 14 cm deep, our bag sits low enough that it reads as a personal item, not a second suitcase.

Should you buy the Jelkin 25 for this?

A 115 cm three-edge total is a rule about perimeter, and the Jelkin 25 sums to 56 cm — under half of it. So the total rule will never catch this bag. The remaining test is the human one: does it disappear under the seat. Buy it if your routes include ANA or JAL, where no personal-item number is published and the only defence is a bag that reads as a personal item.

How to check this yourself before you fly

1. Add length + width + depth, then compare to 115 cm for cabin baggage. A 25 × 17 × 14 cm bag totals 56 cm.
2. Remember the total rule governs cabin baggage, not the personal item. The personal item still has to fit under the seat.
3. Do a real under-seat test at home with a chair. That is the test the gate agent applies, in practice.
4. Keep the bag shallow and visibly small. The failure mode is not the arithmetic — it is looking like a second suitcase.

Keep reading:

• airline personal item size checker — all 19 carriers side by side
• one-centimetre depth cliff — why 15 cm decides six airlines
• the 25 cm bag that fits every sizer — length-vs-depth end to end
• why external dimensions lie about capacity — how we measure bags
• Jelkin 25 — the 25 × 17 × 14 cm bag measured on this page