In and Out 18

Mystery Ranch In and Out 18 is a 17.9L, 0.3kg0.7lb travel backpack measuring 39×20×23cm15.5×8×9in. It fits the carry-on size limit of 36 of 36 major airlines and the personal-item limit of 14 of 26. Under the seat, its 20cm7.9in side is over the 15cm5.9in limit at 6 of the 12 airlines it misses. Specs from offbase.co, checked September 2026.

Volume: 17.9Lfixed size
Weight: 0.3kg0.7lb0.7lb0.3kg
Carry-on: 36/36airlines fit it
Personal item: 14/26under-seat limits

Dimensions: 39×20×23cm15.5×8×9in 15.5×8×9in39×20×23cm
Price: $89 as of September 2026
Laptop: n/a
Opening: Top-loading, Top-loading main compartment; the pack stuffs into its own front pocket for packable storage
Warranty: Lifetime Warranty and repair for the practical lifetime of the pack.
Compartments: n/a
Bottle pockets: 2

Price history

$89 at every weekly check since Oct 5, 2026 (3 checks).

Checked weekly on the brand's US store.

Hydration sleeve

Material: Nylon 100 Robic Ripstop

Original single-size In & Out pack replaced by a Spring 2025 refresh sold as 'In and Out 18' and a companion 'In and Out 25', both with new fabrics/silhouette
Compresses into its own front pocket to roughly the size of a small water bottle
As of Sept 2026 delisted from mysteryranch.com; currently sold only through retail partners

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Last checked: 2026-09. Prices and specs may have changed.

Does the Mystery Ranch In and Out 18 fit airline carry-on limits?

Draw against

Fits under the seatFits under the seat on Ryanair. cabin bag 55×40×20cm21.5×15.5×8in · under the seat 40×30×20cm15.5×12×8in. Bag in cminches, turned to fit.

Flag as a tight fit undercm spare

Airline	Carry-on	Personal item	Cabin-bag weight
Air Arabia	Tight fit (no spare)Tight fit (no spare)	Too bigToo big	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
Air CanadaCabin bag not on every fare	FitsFits	Too bigToo big	No published limitNo published limit
Air FranceCabin bag not on every fare	FitsFits	Too bigToo big	11.7kg to pack (of 12kg shared with personal item)25.8lb to pack (of 26.5lb shared with personal item)
Air India	Tight fit (no spare)Tight fit (no spare)	No published limit	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
AirAsia	FitsFits	Too bigToo big	6.7kg to pack (of 7kg shared with personal item)14.8lb to pack (of 15.4lb shared with personal item)
Alaska Airlines	FitsFits	No published limit	No published limitNo published limit
Allegiant AirCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	No published limitNo published limit
American Airlines	FitsFits	Tight fit (no spare)Tight fit (no spare)	No published limitNo published limit
ANA (All Nippon Airways)	FitsFits	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg shared with personal item)21.4lb to pack (of 22lb shared with personal item)
AviancaCabin bag not on every fare	FitsFits	No published limit	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)
British Airways	FitsFits	Tight fit (no spare)Tight fit (no spare)	No published limitNo published limit
Cebu Pacific	FitsFits	Too bigToo big	9.7kg to pack (of 10kg shared with personal item)21.4lb to pack (of 22lb shared with personal item)
Delta Air Lines	FitsFits	No published limit	No published limitNo published limit
easyJetCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	14.7kg to pack (of 15kg)32.4lb to pack (of 33.1lb)
Emirates	FitsFits	No published limit	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
Frontier AirlinesCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	15.6kg to pack (of 15.9kg)34.4lb to pack (of 35.1lb)
Gol Linhas Aereas	FitsFits	No published limit	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)
IndiGo	FitsFits	No published limit	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
JetBlue Airways	FitsFits	Tight fit (no spare)Tight fit (no spare)	No published limitNo published limit
KLMCabin bag not on every fare	FitsFits	Too bigToo big	11.7kg to pack (of 12kg shared with personal item)25.8lb to pack (of 26.5lb shared with personal item)
LATAM Airlines	FitsFits	Tight fit (no spare)Tight fit (no spare)	11.7kg to pack (of 12kg)25.8lb to pack (of 26.5lb)
LufthansaCabin bag not on every fare	FitsFits	Too bigToo big	7.7kg to pack (of 8kg)17lb to pack (of 17.6lb)
Norwegian Air ShuttleCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg shared with personal item)21.4lb to pack (of 22lb shared with personal item)
Qantas	FitsFits	No published limit	6.7kg to pack (of 7kg shared with personal item)14.8lb to pack (of 15.4lb shared with personal item)
Qatar Airways	FitsFits	No published limit	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
RyanairCabin bag not on every fare	Tight fit (no spare)Tight fit (no spare)	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)
SAS	FitsFits	Too bigToo big	7.7kg to pack (of 8kg)17lb to pack (of 17.6lb)
Singapore Airlines	FitsFits	Too bigToo big	6.7kg to pack (of 7kg)14.8lb to pack (of 15.4lb)
Southwest Airlines	FitsFits	No published limit	No published limitNo published limit
Turkish Airlines	FitsFits	Too bigToo big	7.7kg to pack (of 8kg)17lb to pack (of 17.6lb)
United AirlinesCabin bag not on every fare	FitsFits	FitsFits	No published limitNo published limit
Vietjet Air	FitsFits	Too bigToo big	6.7kg to pack (of 7kg shared with personal item)14.8lb to pack (of 15.4lb shared with personal item)
VolarisCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)
VuelingCabin bag not on every fare	Tight fit (no spare)Tight fit (no spare)	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)
WestJetCabin bag not on every fare	FitsFits	Too bigToo big	No published limitNo published limit
Wizz AirCabin bag not on every fare	FitsFits	Tight fit (no spare)Tight fit (no spare)	9.7kg to pack (of 10kg)21.4lb to pack (of 22lb)

Compared in any orientation against each airline's published size limit. A tight fit has under 2cm to spare, so a packed soft bag may not pass a sizer. Set it to 0 to turn the warning off. Weight is what the airline allows in the cabin minus this bag's empty 0.3kg0.7lb. Limits and sources. Own a different bag? Check it against every airline.