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How to Open a Master Lock Without a Key: 4 Easy Methods!

how to open a master lock without a key

Are you reading this article while you are stuck outside, unable to enter the house because you have forgotten your keys, or cannot open the box with a standard master lock? If so, do not worry. I’m here to help with helpful information.

I’ve been in this situation before. However, I wasn’t so lucky. I had to wait for the locksmith for almost an hour and had to pay a pretty high fee for my negligence. After that incident, I tried several ways to unlock without keys and equipped them as a lifesaver.

So, I’ll share some helpful information on how to open a master lock without a key. In general, this article will cover four ways that I have selected:

  • Using bolt cutters
  • Using a grinding tool
  • Using a padlock shim
  • Using paperclips

Step-by-Step Processes


1. Break the padlock with bolt cutters

This is a quick way that people use to open a standard master lock because the diameter of the shackle will not be too large to make it difficult to open.

Step 1: Choose a suitable pair of bolt cutters

Not all bolt cutters can be used to break a master lock without a key. You need to choose a pair of bolt cutters, which are about 22 or 24 inches long so that you can create enough leverage for unlocking. The longer the bolt cutters, the more likely you can open locks with large shackle diameters.

Step 2: Fix the lock with pliers or a vise

This step is optional. However, it will help you a lot in restricting the movement of the lock. Once fixed, all you need to do is put the cutters in so that its two blades fit the shackle.

Step 3: Apply indirect force on the cutters.

Since the cutters are set in a V shape, you need to clamp the sides of the handles so that they come together and form a straight line. That’s only the theory, therefore, you can stop the process when enough force is applied and the shackle breaks.

2. Open the lock with a grinding tool

It can be anything to grind metal. For example, a grinder or any kind of manual sharpener. This way is to help you push all the pins inside the lock out.

Step 1: Check the direction of the lock

That’s the side where the shackles will fall off. You can check it by looking at the keyhole. If either side appears in many rough places, look for the side with signs of serrations on the key.

Step 2: Smooth the side where the shackle will fall off

Since that will be the side where the pins exist, you’ll need to grind until you see the pins and they fall out.

Step 3: Open the padlock

Now your lock is no longer entangled with any password. All you need to do is find a flat object that can fit into the keyhole. At this position, you just need to twist slightly, and the shackle will fall off.

3. Open the lock with a padlock shim

Here’s a way to remove a master lock without the key without having to physically destroy your padlock. This method is convenient, which I have heard a lot about. Many people have tried and succeeded, so you can consider trying.

Step 1: Prepare tools for the process

A can, pair of scissors, marker, ruler, and pair of pliers are all you’ll need. It may seem like a lot, but most of it is small, which you can easily find in your car or outside the warehouse.

Step 2: Prepare the padlock shim

First, you need to wash the can and cut off its top and bottom. At this point, cut any straight line from bottom to top to turn the can into an aluminum sheet. Now, you can use pliers to flatten the aluminum plate.

Next, rotate the aluminum piece vertically and continue to cut it in half. Then, cut a piece of aluminum into squares with sides about 4-5 cm. Be careful with this step and make sure they are cut into square pieces using a ruler.

Finally, use a pen to divide a square aluminum plate into two parts. Continue drawing an M shape on one side, but round the corners like the shape of a key instead of a regularly pointed triangle. Here, you need to catch the lower part of the letter M to create a space that looks like the shape of two symmetrical keys.

Step 3: Fold the aluminum piece

For the side without the letter M, fold it in half and stop at the marked dividing line.

Next, fold the two sides of the letter M up and fold the excess back. Adjust it so that the end of the folded section touches the marked line. Use pliers to secure the folded parts in place.

Step 4: Place the padlock shim in the shackle hole

First, from the folded piece of aluminum, put the pen in the center to bend the aluminum piece until it fits the shackle hole.

Place the shim into the shackle hole but do not exert too much force. Distorting the shape of the shim will complicate its working principle. The shackle hole to use is the side where the shackle will fall out.

Try to move the shim in a circle from one end to the other. Stay calm if you don’t see movement. This is because it’s looking for the latch inside. Continue moving the shim until you hear a click indicating that you have successfully opened a master padlock without a key.

Some locks will require two shims on either side of the shackle hole to open, which is why I ask you to cut into equal squares instead of one piece.

4. Pick the lock with a paperclip

I have tried using two paperclips, but it is quite difficult and takes a long time for a beginner. So, I want to show you an easier and more helpful way that I have learned from a YouTuber with just a paperclip. This is also a way of opening a master lock without a key where you don’t need to break your lock.

Step 1: Cut one end of the paperclip

Use pliers to cut off one end of the paperclip where there is no circular crease.

Step 2: Place the two sticks on either side of the paperclip to fit snugly into the lock.

Choose a stapler that is small enough to fit into the keyhole. If it’s bigger or smaller, it cannot put enough pressure on the pins inside.

Step 3: Use a screwdriver to unlock

At this moment, it will act as a lever for the lock. Use a screwdriver with a crossbar instead of a cross, which is small enough to be inserted into the keyhole. Then, with slight movements, you will be able to open the lock when the shackle comes out.


  • Check the lock’s model number and manufacturer on its body or bottom, which will be important information when you cannot open the lock yourself and need help from a locksmith.
  • If you get a chance, order a transparent padlock so you can understand its mechanism, which will make it easier to locate the parts in the event of a bad situation.


There are many ways to open a classic lock because its security is not high. However, knowing the theory will not open the lock, you will also need to have lots of patience and practice. Having your master lock lost key is annoying, so when you successfully open the lock, equip yourself with methods to prevent the recurrence.

In this article on how to open a master lock without a key, I have summarized four ways to unlock a master lock without a key, which I have tried and succeeded in. So, I want to share how to do it. If you want to know more content on a similar topic, feel free to leave a comment or send us an email.

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