Why Do Backpacks Have 2 Zippers?


So you’ve overloaded your backpack and the zippers are bursting at the seams. Your zippers are bursting open with the contents falling out as you walk. Ever wonder if it would be better to only have 1 zipper? So, why do backpacks have 2 zippers?

There are a few reasons why backpacks use 2 zippers. The double zipper system adds strength to the bag under load, allows you to lock the bag, unzip a small part of the bag, and it works for both left and right handed people. Removing a zipper would make your bag weaker and less functional.

So there’s obviously benefits to the 2 zipper system, but how can I make them work for me? In the rest of this article I’ll explain how to use the double zipper system to get the most out of your bag.

Why Do Backpacks Have 2 Zippers?

Honestly, I never even realized my backpack had 2 zippers until a friend of mine asked me about them. I decided to reach out to a few of the major hiking backpack manufacturers to figure since I had no idea why packs had 2 zippers. After being forwarded down the customer service line I finally talked to a man that knew what he was talking about.

He explained that a double zipper system adds both strength and durability to your backpack. A double zipper system can be partially unzipped to suit your needs and it works equally for everybody regardless of their preferred hand orientation. Here are the main benefits to using a 2 zipper system in your backpack.

  1. Adds Strength to Your Bag: Your zipper has to be able to support your packs load. An overloaded pack will pull a single zipper apart and then you’d be screwed. With a 2nd zipper you should still be able to close your bag if 1 zipper fails.
  2. Open Part of The Bag: It’s nice to be able to quickly reach into a corner of your pack without opening up the entire compartment.
  3. Lock The Bag: Throw a lock on your bag when sending it through checked luggage.
  4. Left and Right Handed People: Left handed people prefer to open their backpack from right to left so they can use their dominant hand. You can’t do that with a single zipper.
  5. Easier to Close With 2 Hands: Closing an overloaded bag is hard with a single zipper.

It Adds Strength To The Bag

Your backpacks zipper carries a surprising amount of your packs load. The surrounding fabric helps, but the majority of your packs weight will center on the zippers.

Would you rather have 2 zippers holding all that weight or 1? The answer is obvious! Using a double zipper system spreads the weight out and reduces the likelihood of zipper failure. You can always use your 2nd zipper even if a single zipper breaks.

Always Close Your Zippers At The Side

Have you ever walked with a heavy pack and had your zippers slowly work their way apart. Before you know it your entire backpack is open. This is very common with people that overload their pack and let their zippers meet at the top. As you walk gravity and the weight of your packs load slowly pull down the zippers.

Thankfully, there’s an easy solution to this problem. Always zip your backpack shut with the zippers on the far left or right of your pack. It doesn’t matter which way you zip it as long as the zipper ends up on the bottom side of your pack.

Allows You to Open a Small Part of The Backpack

You don’t always want to open up your entire pack to get inside. There’s been so many times where I’ve been caught in a rainstorm and need to quickly open up my pack without getting the contents wet. Using a 2nd zipper allows you to only unzip the portion of your pack you need to access. I actually leave a small hole on the side of my pack to run the water line from my hydration bladder.

You might also want to pick up a pack liner if you’ll be spending a few days carrying a hiking backpack. A pack liner will keep the inside of your bag dry in even the worst downpour. Most people choose a dedicated pack liner like the Osprey Ultralight Liner, but I prefer standard heavy duty compactor bags(this is what I’m talking about).

You Can Lock Your Bag When Using It as Luggage

Lock your backpacks zippers if you ever plan on checking it in the cargo hold. I had an unfortunate experience where the flight attendants forced me to check my carry on backpack and the zippers ended up coming undone. The zipper must have gotten caught on something as my pack made its way down the belt.

Thankfully, I didn’t lose anything that’s irreplaceable, but it was still a pain in the butt. All it would have taken is a cheap lock to make sure my zippers wouldn’t open up. It’s not going to keep out security, but it least the bag won’t pop open.

Better For Left and Right Handed People

Backpacks are one of the few things in life that are designed for both left and right handed people. The 2 zipper system allows you to open up your backpack from either the left or right side. Left handed people usually want to open up bags using their dominant hand.

So the zippers would rest on the right side of their pack and be opened from right to left. Right handed people prefer to open their bags the opposite way.

Easier to Close an Overloaded Bag

Have you ever tried to close a suitcase that’s very obviously overloaded? Anybody that’s traveled with kids/women has probably dealt with this issue. You have to use your entire body weight to manhandle the bag and those zippers.

The second zipper allows you to get past those difficult spots when the first zipper won’t seem to budge. Without it you’d most likely be screwed and unable to close the bag.

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