Jelkin 25 internal volume, by geometry: the 5.95 L outside is not the 4.2 L inside

Short answer: the Jelkin 25 measures 25 × 17 × 14 cm on the outside, a gross volume of 5.95 L. Subtract the 12 mm faux-shearling pile and the structured frame and lining, and the usable interior is about 4.2 L — a geometry-based estimate, not a physical pour. That is still enough for the seven things it is built to hold.

Outside versus inside

External dimensions are what the sizer checks. Internal volume is what you pack. They are not the same number, and the gap is where honest bag specs live.

Measure	Value	How we got it
External (gross)	25 × 17 × 14 cm = 5.95 L	L × W × D
Material thickness	~12 mm pile + frame/lining	specified
Usable interior (est.)	~4.2 L	gross minus ~30% for walls/pile, geometric estimate

This is an estimate, stated as one

We did not pour rice into the bag; we computed the interior from the external shell minus a realistic allowance for the 12 mm pile and the stiffened frame panels. The true number is in the 3.8–4.5 L band depending on how tightly the shearling is compressed. Treating it as a precise "measured" figure would be the kind of spec claim we avoid.

What 4.2 L holds

The bag is built around seven items: phone, wallet, keys, AirPods, lip gloss, sunglasses, iPad mini. Those total well under 4.2 L, which is why they fit without fighting the zip — and why the bag stays under the 15 cm depth wall even when full.

Should you buy the Jelkin 25 for this?

The honest number is ~4.2 L usable inside a 5.95 L shell, and we label it an estimate rather than a pour. If you need to carry a laptop, shoes or two nights of clothes, buy a carry-on instead — this bag will not stretch. If you need seven small essentials to sit without fighting the zip while the bag stays under the 15 cm depth wall, 4.2 L is precisely the right size.

How to check this yourself before you fly

1. Subtract wall and pile thickness from any external volume you are quoted. 12 mm of shearling pile plus a frame costs roughly 30%.
2. Be suspicious of "measured" internal volumes. Most are the external product of three numbers with nothing subtracted.
3. Pack the seven items and close the zip. If the zip fights, the bag is full — and overfilled means over 15 cm deep.
4. Treat 3.8–4.5 L as the realistic band for this bag depending on how tightly the pile compresses.

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