What Size Backpack Do I Need? A Complete Guide to Choosing the Perfect Fit
What Size Backpack Do I Need? A Complete Guide to Choosing the Perfect Fit Introduction For over 10 years, we have been helping backpackers find the ideal outdoor gear. We understand that selecting the correct size backpack can make the difference between a successful adventure and a disastrous one. Whether going on a day hike, a multi-day camping trip, or traveling internationally, choosing the wrong size pack can lead to discomfort, insufficient packing space, or worse—you might forget to bring something important. Our guide will help you determine the appropriate size backpack for any activity, allowing you to prioritize comfort and enjoyment on your journey. Key Takeaways Backpacks range from 19L (day use) to 45L+ (extended camping trips). Match your size to the length of the activity and type of gear you’re using. Proper torso measurement is essential for fitting and comfort while on your trip and for weight distribution. Think about how you like to pack. Minimalist packers can usually go smaller. Remember to try it on for size before you buy, if possible. What size backpack do I need? Day hikes: 20-30L Weekend trips: 30-40L Week-long trips: 40-60L Extended trips: 60L+. Key factors include: Trip duration and activity type Personal packing style and gear requirements Body size and comfort preferences Weather conditions and seasonal gear needs Understanding Backpack Sizing Most backpack volumes are described in liters (L), a measure of total internal volume. Backpack size can be standardized and means the same globally, unlike clothing. Most manufacturers will also give you dimensions in inches or centimeters to grasp the actual physical footprint of the backpack. Volume vs. dimensions matter differently: A 30L pack might be tall and narrow (better for hiking) or wide and short (better for travel). Consider both measurements when determining what backpack size I need for your specific activities. Backpack Size Categories Small Packs (19-24L) Ideal for: Day hikes, city strolling, school, and work commutes. It contains water, snacks, first aid, a light layer, and small electronics. The pros are that it is lightweight, has minimal bulk, and is perfect for short trips. Medium Packs (24-35L) Best for: Day hiking with extra gear, weekend trips, school/work with a laptop. What fits:Everything from small packs plus camera gear, extra clothing, and lunch. Benefits: Versatile size, comfortable for extended wear Large Packs (30-45L+) Best for: Multi-day camping, backpacking trips, extended travel. What fits: Sleeping gear, cooking equipment, and multiple clothing changes. Benefits: Sufficient space for self-sufficient adventures Matching Size to Activity Hiking Adventures For what size hiking pack do I need? Consider your typical hiking style: Day Hiking (4-8 hours): 20-30L handles water, food, safety gear, and weather protection. Perfect for most trail conditions without overnight gear. For Multi-Day Hiking: A 40-60L backpack allows space for sleeping systems, cooking gear, and supplies for multiple days. The best backpack size for hiking depends on the trail’s infrastructure and the weather. Camping Expeditions What size backpacking pack do I need for camping? Base your choice on trip length and group dynamics: Weekend Camping: A 35-45L would work for campgrounds that have facilities. For Backcountry Camping: A 50-65L will work well for a full carry for a self-sufficient camping experience. For Extended Expeditions: A backpack of 65L or more will work for multi-day adventures, or in winter conditions. Travel Applications The appropriate size of a travel backpack is dictated by how you travel and what your airline’s restrictions are: Carry-On Travel– 35-40L maximum for most airlines (always check specifics). Extended travel- 45-55L in size for updated travel where you plan to visit multiple climates. Backpacking Travel- 55-70L for trips staying in hostels, carrying all your belongings. Essential Considerations In Selecting Size Duration of Trip: Longer trips require more consumables, but can be compensated for with optimized packing. Packing for a 3-day trip, with efficient gear choices and optimized packing, can take no more than 20% more space than packing for a 1-day trip. Climate Conditions: Cold weather gear takes significantly more space. Winter camping might require a 50% larger capacity than summer trips. Packing Style: Minimalist packers can go 20-30% smaller than average recommendations. “Just-in-case” packers should size up accordingly. Airline Restrictions: Limits on international carry-ons differ. Research specific airline requirements when deciding what size backpack for travel works best. Ensuring Comfort and Fit Measuring Your Torso Length Locate your C7 vertebra (base of neck, prominent bone) Find your iliac crest (hip bone top) Measure the straight-line distance between these points Match measurement to the manufacturer’s sizing chart Torso Length Guide: Short: 15-17 inches (38-43 cm) Medium: 17-19 inches (43-48 cm) Long: 19-21 inches (48-53 cm) Weight Distribution Tips When properly fitted, the pack distributes 80% of the pack weight to the hips rather than the shoulders. Look for a hip belt that is padded, adjustable torso length to accommodate height, and load-lifter straps. Avoid the common mistakes: Oversizing: Oversizing can lead to overpacking and unnecessary weight/bulk. More isn’t better! Ignoring Fit: The best size is pointless if it does not fit your body. Always test with some weight before buying. One-Size-Fits-All: Different activities require different characteristics in a pack. A travel pack is not best for hiking and vice versa. Forgetting Compression: Modern packs compress significantly when not full. A 40L pack can work for 25L loads with proper compression systems. Step-by-Step Selection Guide Step 1: Determine Your Major Use. Identify what the pack will mainly be used for: day hiking, weekend camping, international travel, or daily use. Step 2: Quality or Quantity. Are you a minimalist who takes only the essentials or someone who likes the safety of backup options? Step 3: Check Your Torso Length. Use the guide linked above to ensure it fits regardless of pack size. Step 4: Use Size To Meet Need. Use our recommendation for activity type as starting points, but adjust for personal preference. Step 5: Give It A Trial. Load the pack with appropriate weight, put it on, and wear it for around 20-30 minutes. When to Go Up or