40 × 20 × 25 cm under-seat bag: who uses it, and bags that fit

40 × 20 × 25 cm is 15.7 × 7.9 × 9.8 in, about 20 litres. It's the exact under-seat bag limit on Arajet (personal item).

A bag "fits" here when it has at least 1 cm (0.4 in) to spare on every side, turned whichever way works. 4 of the bags we track do; another 29 are within a centimeter.

Bags that fit 40 × 20 × 25 cm

Personal-item bag (2)

CabinZero Classic Flight Backpack 12L

Personal-item bag · 34 × 19 × 15 cm (13.4 × 7.5 × 5.9 in)

Fits 5 cm (2 in) to spare on the depth

See it at CabinZero ↗

Herschel Retreat Backpack Mini

Personal-item bag · 11 × 8.9 × 4.9 in (28 × 22.5 × 12.5 cm)

Fits 2.5 cm (1 in) to spare on the width

See it at Herschel ↗

Duffel / weekender (1)

CALPAK Luka Mini Duffel in Vegan Leather

Duffel / weekender · 14.5 × 9.3 × 6.8 in (36.8 × 23.5 × 17.1 cm)

Fits 1.5 cm (0.6 in) to spare on the width

See it at CALPAK ↗

Tote (1)

Eagle Creek Migrate Tote Bag

Tote · 30 × 20 × 17 cm (12 × 8 × 7 in)

Fits 3 cm (1.2 in) to spare on the depth

See it at Eagle Creek ↗

Other common sizes

• 55 × 40 × 20 cm
• 45 × 36 × 20 cm
• 22 × 14 × 9 in
• 56 × 45 × 25 cm
• 40 × 30 × 20 cm
• 18 × 14 × 8 in
• 40 × 30 × 15 cm
• 50 × 40 × 20 cm
• 55 × 35 × 25 cm
• 56 × 36 × 23 cm
• 17 × 13 × 9 in
• 16 × 12 × 6 in
• 17 × 10 × 9 in
• 55 × 40 × 23 cm
• 40 × 30 × 25 cm
• 35 × 20 × 20 cm

Airline limits checked 5 October 2026; bag sizes are each brand's published dimensions. Airline staff have the final say at the gate.