KS Ultralight Tao vs. Tom Bihn Brain Bag

Two carry-on travel backpacks, compared spec for spec.

KS Ultralight Tao

Front facing view of the KS Ultralight Tao
Capacity35 L
Weight0.3 kg
Dimensions71×30×18 cm
Airline fit1%
Price$150

Feature by feature

KS Ultralight TaoFeatureTom Bihn Brain Bag
Storage
N Compression 4
None Expanded Capacity None
0 Opening 4
top Passport top
N Passthrough N
Carry
Y Backpack Y
removable Hip Belt removable
removable Sternum Strap removable
Inside
N Laptop N
2 Main Compartments 6
N Organizer Y
Outside
× Hard Shell ×
N Rain-fly N
N Water Bottle Holder 1, side
Y Water Resistant Y
Material
X-pac VX 07YKK "waterproof zip"525 Ballistic Nylon

Tom Bihn Brain Bag

Front facing view of the Tom Bihn Brain Bag
Capacity36 L
Weight1.3 kg
Dimensions46×36×23 cm
Airline fit66%
Price$240

Key differences between the KS Ultralight Tao and Tom Bihn Brain Bag

Both have: passport pocket, backpack straps, hip belt, sternum strap, water resistant.

Which airlines take each bag as a carry-on

We checked both bags against the carry-on size limits of 189 airlines. 2 accept both. 0 accept only the KS Ultralight Tao, and 123 accept only the Tom Bihn Brain Bag.

Only the Tom Bihn Brain Bag fits

Adria Airways, Aegean Airlines, Aer Lingus, Aeroflot, Aeromexico, Air Asia, Air Astana, Air Canada, Air Caraibes, Air Europa, Air Koryo, Air Macau, Air New Zealand, Air Nostrum, Air Tahiti Nui, Air Wisconsin, AirAsiaX, Alaska Airlines, All Nipon Airways, Allegiant Air, American Airlines, ANA, Atlas Global, Austrian, Avianca , Azerbaijan Airlines, Azul Linhas, Bahamasair, Bangkok Airways, Biman Bangladesh, British Airways, Brussels Airlines, Cambodia Angkor Air, Caribbean Airlines, Cathay Pacific, Cebu Pacific, China Airlines, China Southern, CommutAir, Conviasa, Copa Airlines, Croatia Air, Cubana de Aviacion, Czech Airlines, Delta Airlines, Dragonair, EL AL, Ethiopian Airlines, Etihad Airways, Eurowings, EVA Air, Fiji Airways, Finnair, Flair Air, Frontier Airlines, Garuda Indonesia, Gol Linhas Aereas, Hainan Airlines, Hawaiian Airlines, Hong Kong Airlines, Iberia, Interjet, Iran Air, Iran Aseman Air, Island Air, Japan Airlines, Jet2, jetBlue Airways, Jetstar Airways, Jetstar Asia, Korean Air, Kulula, Kuwait Air, LOT Polish, Lufthansa, Mahan Air, Malaysia Airlines, Mango, Mesa Airlines, Middle East Airlines, Monarch Airlines, Norwegian, Oman Air, Onur Air, Peach, PenAir, Philippine Airlines, Porter Airlines, Qantas Airways, Qatar Airways, Ravn Alaska, Republic Airways, Royal Air Morocco, Royal Jordanian, SAS Scandinavian, Saudi Arabian Airlines, Scoot, Sichuan Airlines, SilkAir, Silver Airways, Singapore Airlines, Skywest, Inc., South African Airways, Southwest Airlines, SpiceJet, Spirit Airlines, SriLankan Airlines, Sun Country, Swiss Int'l Air Lines, TAAG Angola, TAM Airlines, Thai Airways, Tiger Airways, Trans States, Travel Service Airlines, Turkish Airlines, United Airlines, Ural Airlines, Uzbekistan Air, Vietnam Airlines, Virgin Atlantic, WestJet, WOW Airlines.

KS Ultralight Tao vs. Tom Bihn Brain Bag: which should you pack?

The Tom Bihn Brain Bag carries 1L more than the KS Ultralight Tao (35L vs. 36L), while the KS Ultralight Tao is the lighter pack at 0.3kg (vs. 1.3kg). For carry-on flexibility, the Tom Bihn Brain Bag fits 66% of the airlines we track — the higher of the two. If you prioritise packing volume, choose the Tom Bihn Brain Bag; if you want to travel lighter, the KS Ultralight Tao is the better call.