Whether a 70L backpack is too big really depends on your travel style and needs. Large rucksacks around 70 liters are often used for extended trips, camping, or hiking where you need to carry extra gear, clothing, or equipment. For shorter trips or airline travel, this size may be considered oversized and could be difficult to manage or store. Always check airline baggage policies, as many carriers have size and weight restrictions for carry-ons and checked bags. If you prefer to pack light or want more mobility, a smaller rucksack might be a better fit.

Large rucksacks can range from about 50L up to 80L or more, with some specialty backpacks designed for expeditions or long-term travel. The largest size you can buy at Walmart typically depends on the intended use—hiking, travel, or everyday carry. Keep in mind, bigger isn’t always better; oversized backpacks can be heavy and challenging to carry when fully loaded. Consider your comfort, how much you need to pack, and transportation requirements before choosing the largest option available.

While the terms "rucksack" and "backpack" are often used interchangeably, there are some subtle differences.

• Rucksacks usually refer to larger, more rugged bags designed for outdoor activities like hiking or camping. They often have extra straps, compartments, and features for carrying gear.
• Backpacks can be any bag worn on your back, including those for school, work, or travel. They might be smaller and simpler in design.

A 40L rucksack is often suitable as a carry-on for many airlines, but it’s important to check the specific size requirements of your carrier.

• Most airlines allow carry-ons up to about 22 x 14 x 9 inches, and many 40L backpacks fit within these dimensions.
• Look for rucksacks labeled as "flight approved" or "TSA friendly" for added convenience.

Choosing the right size rucksack depends on how you plan to use it.

• For daily use or school, a smaller backpack (15L–30L) is usually enough.
• For weekend trips or light travel, consider a medium size (30L–50L).
• For multi-day hikes or longer travel, a large rucksack (50L–70L+) might be best.