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Cracking a Combination Lock – Easy and Simple Opening

Forgot your combination lock code? In this guide, you'll learn two proven methods to crack a combination lock: the rope method for quick grip and the decoder technique to find out the exact combination. Step by step, we explain how to retrieve your forgotten code in just a few minutes, including frequently asked questions about resetting combination locks and TSA locks.

Author: Ties

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If you have forgotten the 4-digit lock code, there are two methods to crack your combination lock. With this guide, you will discover how to find the code of any combination lock in just a few seconds! Keep in mind, this skill is intended for legal use only. I share this knowledge purely to help you open your own combination locks for which you have forgotten the code.

For opening regular padlocks (so not combination or digital locks), you cannot use these techniques. You will need a lockpick set.

Close-up of a combination lock with four dials, ready to be cracked using the rope method

Basics of Cracking a Combination Lock

A combination lock consists of a series of dials, each often having three or four digits. These dials are arranged around a central axis, with a keyhole in the center of the mechanism.

The first technique involves turning the dials and paying attention to changes in resistance or sound signals that indicate the correct position. This method helps to find the correct combination.

Method 1: Cracking a 4-Digit Combination Lock with Rope

When opening/cracking a combination lock, a piece of rope can be used to create an improvised handle. This gives you better grip on the lock.

Supplies needed to crack a combination lock: a 30 cm rope and the combination lock

Constant pressure on the shackle is crucial when cracking a combination lock. You create friction on the adjustment wheels of the lock. Once an adjustment wheel is turned to the correct number, you will feel a distinct click and a slight upward movement of the shackle.

A clear click is the sign that you are one step closer to opening the combination lock. You can then proceed to adjust the next wheel. Repeat until all wheels are adjusted and the combination lock is successfully cracked.

Step 1: Finding the Right Number Combination

Threading the rope through the shackle of the combination lock for better grip

First, you need to thread the rope through the shackle of the lock. This will be your improvised handle, providing you with a sturdier and stronger grip on the lock to facilitate cracking it.

Step 2: Effectively Cracking the Combination Lock

Thumb pressing on the top of the combination lock while the wheel is being turned

When you hold the rope firmly in your hands, you should press down as hard as possible with your thumb on the top of the lock. Make sure to maintain the same pressure on the lock throughout the process. While doing this, you should carefully turn each wheel. You will quickly find the number that is the hardest to turn.

Step 3: Open the Lock!

Begin to gradually turn the number wheel until you hear a distinct click and feel the shackle move slightly upward. Check the wheel and note the number at which it clicked. Then gradually turn the wheel further to check it again. If it consistently clicks at the same number with each turn, you have successfully found the first digit of the code.

Step-by-step finding each digit by feeling for the click

Repeat the same process as with the other dials until you have deciphered the second and third numbers of your combination. For the last dial of your combination lock, it is now just a matter of maintaining steady pressure and allowing the remaining dial to make a full rotation slowly. When turning this dial, the shackle of the lock should open.

Successfully opened combination lock after finding the right combination

When the lock opens, you have successfully cracked the code of the combination lock. It may be that your combination lock does not respond to this method. In that case, your success might lie in the second method. With the following method, you will open a combination lock by utilizing another weakness of the lock.

Method 2: Cracking a Combination Lock with a Decoder

For the second method, you will need a very thin piece of metal. This thin piece of metal can then be slid between the housing of the lock and the gear. We have some handy tools from well-known brands to help you with this, namely:

What Happens Inside the Combination Lock?

First, take a good look at how a dial of a combination lock looks. Each dial has internal teeth that can fall into a ring located inside the combination lock.

Inside of a combination dial with visible teeth and internal ring

Subtly Feeling with Your Decoder

With your thin decoder (only 0.2 mm thick), you will feel along the inner edge of the combination dial. There is a small rotating inner ring (“core ring”) that rotates with the outer dial. This core ring has a small notch that you can clearly feel as you slide your decoder past it.

Core ring in the combination dial with the notch you need to feel

Recognizing the Notch

When you are turning slowly, you will suddenly feel the decoder drop into a notch. This is exactly the point you are looking for, a tangible click! This point is marked with a blue circle in the next image:

Decoder finds the notch in the combination lock, marked with a blue circle

This is How You Gather the Right Digits

For each dial, you do the same. This way, you limit the number of combinations you will need to open the combination lock.

All three number dials of a combination lock aligned next to each other

Decoder Technique in Action

Watch closely how the decoder glides along the inner side and finds the notch. You will feel a distinct click when the decoder falls into the right position. This quickly reveals the correct position of all notches. The code discovered here is: 5-5-1. Let’s look at the final step to find out how to crack your code!

Animation showing how the decoder glides along the edge of the dial and finds the notch

With the code 5-5-1, you have reduced the combination possibilities from 1000 to just 10! Turn all the digits together to the next position and test if the lock can open. If the lock does not open at 6-6-2, try 7-7-3 and pull the lever. If the combination lock does not open, try the next digits until the lock is open!

Animation of trying combinations 6-6-2, 7-7-3 until the lock opens at 9-9-5

Success! Any questions?

Yes! The combination was 9-9-5! You will notice that when all the correct grooves are aligned, you suddenly feel a slight movement in the shackle. It almost pops open by itself, a magical moment guaranteed! This is how you discovered the forgotten combination of your combination lock!

How do you open a combination lock if you have forgotten the code?
Use a decoder. Listen and feel for clicks while turning the dials. This will help you find the right combination.
My combination lock on my suitcase won’t open, what can I do?
First, check if the code has been entered correctly. If this does not work, use a decoder as explained in this message to open the lock.
How do I reset a combination lock if I have forgotten the code?
Usually, you need to open the lock before you can reset the code. Use a decoder to open the lock, then you can reset the lock via the reset button or procedure.
Can I open a combination lock without a code?
Yes, by using a decoder you can find the right combination without the original code.
How many combinations does a combination lock with three digits have?
A combination lock with three digits has 1000 possible combinations (from 000 to 999).
How do I change the code of my combination lock?
First, set your current code and open the lock. Then use the reset button (often a small button or pin) and set a new code.
What is a TSA combination lock and how does it work?
A TSA lock is designed for travel and can be opened by airport security with a special key without damaging the lock. You simply use it with your chosen number combination.
Ties

Ties of Lockpickings

Ties has been involved with lockpick sets for over ten years. Not to open locks, but to understand how they work. Since 2011, he has been selling lockpick sets. In 2015, he started Lockpickings because he thought: more people should be able to do this. He writes about lockpicking. For beginners who are still all thumbs. For nerds who want to know how a pin really moves. And for anyone who wants to understand why one tool works better than another. Ties tests a lot. Too much, actually. But well, someone has to do it. He lives in Europe and believes it’s important for people to understand what lockpicking is really about: understanding how your lock works. Precision. Patience. And that satisfying feeling when you figure it out.

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