1.Core Difference: Adaptation to Usage Scenarios   Duffel Bag: Ideal for short trips like 1-3 day weekend getaways, gym sessions (as a gym duffel bag), or short business trips. Opt for a waterproof duffel bag if you often encounter rain or spills. It features a wide opening for easy access to items, making it perfect for carrying bulky belongings like sports gear, folded clothes, or travel essentials—great as a carry-on duffel bag for flights.​ Backpack: Suited for long trips (over 4 days), daily commutes (choose a commuter backpack), or outdoor activities like hiking (go for a hiking backpack). A backpack with laptop compartment is a must for professionals, as it frees up both hands completely—ideal for carrying a laptop, documents, water bottle, and snacks all at once.​   2. Comparison of Carrying Convenience​ Duffel Bag: Mostly designed with single-shoulder or hand-carry straps (look for a duffel bag with padded straps to reduce shoulder strain). It can cause fatigue when carried long-term due to concentrated pressure, but its lightweight design lets you quickly lift it through airport security or in crowded subways—perfect as a travel duffel bag for hassle-free transit.​ Backpack: Equipped with a dual-shoulder pressure-distribution design; a ergonomic backpack with padded back panels offers extra comfort. Some models add waist supports and chest straps (key for outdoor backpacks), evenly spreading weight across the back and shoulders for long walks—great for city trekking or daily commutes where you need all-day comfort.​ 3. Storage and Capacity Features​ Duffel Bag: Offers flexible capacity (many expandable duffel bag styles go from 30L to 50L), but has fewer internal compartments. Pair it with packing cubes if you want to avoid clutter—ideal for those who prefer a large duffel bag for bulky items but don’t need strict organization.​ Backpack: Boasts abundant compartments: a dedicated laptop compartment (fits 13-15.6 inch devices), side pockets for water bottles/umbrellas, and hidden pockets for passports. A waterproof backpack adds protection for electronics, while a small backpack (20-25L) works for daily commutes—perfect for categorizing documents, gadgets, and daily essentials. ​ 4. Selection Recommendations​ Choose a Duffel Bag if: You need a short trip duffel bag, prioritize easy item access, carry single-type items (sports gear, travel clothes), or want a carry-on duffel for flights.​ Choose a Backpack if: You’re after a long trip backpack, need to free up hands (for commuting or hiking), carry multiple items (laptop + clothes + toiletries), or want an organized backpack with compartments for work or travel.​